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Gear Talk => EOS Bodies - For Stills => Topic started by: NormanBates on January 20, 2013, 06:12:24 AM

Title: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 20, 2013, 06:12:24 AM
I have to decide between APS-C and full frame, and one of the things to look at is sharpness.

With APS-C, as opposed to full frame, you're only using the central portion of the image circle, the sweet spot: you're not using those blurry corners, and this should lead to sharper pictures. On the other hand, because the sensor is smaller but final image resolution is the same, you're blowing up the analog image that the lens projects on the sensor; this is bad, because every defect will be magnified. Which force is bigger?

I ran some tests trying to find out, shooting stills with a 5D2.

My conclusion: as a general rule, a lens will always be sharper on full frame than on APS-C, both in the center and in the corners.

You can see the tests and read a bit more about them here:
http://www.similaar.com/foto/lenstestsff/lenstestsff.html (http://www.similaar.com/foto/lenstestsff/lenstestsff.html)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 20, 2013, 06:51:16 AM
Errr..... you're not "blowing up the analogue image bigger" if the APS or FF or any other sensor size for that matter have the same number of digital info capture points - pixels. MP is MP of digital info - the computer program enlarges the image.

The issue on smaller sensor regarding "enlarging" is can the smaller pixels capture the info accurately. In that respect they are certainly improving.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 20, 2013, 07:10:13 AM
What I mean is that you've got an image circle, a bunch of photons that are projected back by the lens. This is anlogue. You put the same ~20 million photosites behind that in both cases, but on APS-C each of them is smaller.

If you want to think it like this, it's as if, instead of a ~20 Mpix full frame sensor, you had a ~50 Mpix full frame sensor, and then you used only the central portion, and enlarged it so that it is now the full image (and this is where my "magnyfy issues" argument comes in: you are enlarging the image, and this magnifies any defects in the lens).

So, yes, as you say, the thing is that the pixels are smaller, and this reduces quality.

In any case, the proof is in the pudding: fullframe gives a lot more detail.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 20, 2013, 07:23:56 AM
No surprise there.  But just want to point out, this is a DxO-like conclusion.  You used a 5DII for the test, I can say from experience that in many situations, the APS-C sensor in my 7D delivered sharper pictures than my 5DII, by virtue of its better AF system.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: East Wind Photography on January 20, 2013, 07:27:15 AM
I don't disagree with your conclusion.  The only reason I might upgrade to an aps-c from my 5d3 would be if it was also around 22mp.  However your test results would be more compelling if the target distance was also compared when at the same distance.  Effective comparison of sensor sharpness should keep all other factors the same.  Distance plays an important factor in a lenses resolving ability.

Still I do agree with your results when applied to the field.  I shoot primarily wildlife now with my 5d3 and resolving ability isn't even comparible  to my 7d.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 20, 2013, 07:41:24 AM
Nice work, but have a look at center crop APS-C 24 mm, how come that f9 is sharper than f5.6?

You already mentioned DoF on your site:
Quote
Add to that the fact that for a given depth of field you're closing down the iris further on your full frame lens (and this helps sharpness too) and I think the result will be pretty much general.
When you want large DoF than we're talking about f/8 (APS-C) and f/11 (FF) or so. IMO closing down even further makes the image actually softer, due to diffraction and lens design.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 20, 2013, 07:42:08 AM
I don't disagree with your conclusion.  The only reason I might upgrade to an aps-c from my 5d3 would be if it was also around 22mp.  However your test results would be more compelling if the target distance was also compared when at the same distance.  Effective comparison of sensor sharpness should keep all other factors the same.  Distance plays an important factor in a lenses resolving ability.

Still I do agree with your results when applied to the field.  I shoot primarily wildlife now with my 5d3 and resolving ability isn't even comparible  to my 7d.

+1 to that in practical application.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: aznable on January 20, 2013, 08:51:21 AM
No surprise there.  But just want to point out, this is a DxO-like conclusion.  You used a 5DII for the test, I can say from experience that in many situations, the APS-C sensor in my 7D delivered sharper pictures than my 5DII, by virtue of its better AF system.

a lot of people forgot that a camera it's not just a sensor
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 20, 2013, 10:14:56 AM
No surprise there.  But just want to point out, this is a DxO-like conclusion.  You used a 5DII for the test, I can say from experience that in many situations, the APS-C sensor in my 7D delivered sharper pictures than my 5DII, by virtue of its better AF system.

Indeed. You may also notice that I listed my best 3 lenses there, and none of them has AF.

Nearly everything on that site was created because I needed it, including these tests. They're made for me, and designed for my very special needs.
Everybody should test their equipment to see how well it fits their needs, what can be done and what's not a good idea, and where there's room for improvement. I'm just sharing my results. They shouldn't stop anybody else from running their own tests.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 20, 2013, 10:28:24 AM
All else being equal, especially including the final print size (a factor which often gets ignored and confused with respect to pixel peeping), the larger the format, the better the image quality in every aspect. That includes sharpness as well as noise / grain as well as dynamic range as well as anything else you care to mention.

Of course, all else is never actually equal, which is why it's important to compare complete systems. Neoruanatomist made that point; better theoretical maximum image quality is useless if you can't properly operate (in the specific case, focus) the equipment.

There's another factor to consider. Image quality with even entry-level DSLRs and kit lenses is superlative. Anything going to the Web, 4x6 prints, and even 8x10 prints...there's no practical real-world image quality difference between a Rebel and medium format (with the exception that you can more easily get a greater amount of background separation with the larger format).

Once you're printing on a machine that won't sit on your desktop, though, the difference between the different formats starts to become apparent. You can make a great roadside billboard with a Rebel and a kit lens, but walk up to a pair of door-sized fine art prints, one made with said Rebel and the other with an 8x10 view camera, and even your half-blind great uncle will be able to tell the difference.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 20, 2013, 11:30:00 AM
There are certain situations where a crop delivers higher resolution than a FF with the same lens (even disregarding DoF, AF and the corners). Roger M. Clark has nice shots of the moon with the 5D2 and the 7D that show this:

www.clarkvision.com/articles/digital.sensor.performance.summary (http://www.clarkvision.com/articles/digital.sensor.performance.summary)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 20, 2013, 11:52:01 AM
Indeed, if you keep lens and distance constant, APS-C will give you lots more detail. Because it's just as if you had a 50 Mpix full frame body and cropped the center of the image.

But that's not my usual scenario. For me, the right comparison is "Elmarit-R 35mm f/2.8 on APS-C set at f/2.8" vs "Summilux-R 50mm f/1.4 on full frame set at f/4.5". Similar FoV, similar DoF --> full frame is clearly sharper.

As I said, if this is not the way you shoot, run your own tests designed for your usual scenario (actually, you should run them anyway!).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 20, 2013, 12:02:57 PM
Indeed, if you keep lens and distance constant, APS-C will give you lots more detail....

Yes, at low ISO.  But once you raise the ISO a bit, the FF delivers more detail in focal length-limited situations.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 20, 2013, 12:06:53 PM


My conclusion: as a general rule, a lens will always be sharper on full frame than on APS-C, both in the center and in the corners.

There is no general rule. Whether FF beats APS-C depends upon distance, size of the detail on the subject and whether it will span the length of two pixels, how good the light is etc as well as on sensor and and lens. It is remarkable how often in these forums someone does a restricted series of experiments and then claims a general rule.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: East Wind Photography on January 20, 2013, 12:27:07 PM
I never did buy those as well.  The atmospheric distortion can change from 1 second to the next affecting any perceived increase or decrease in resolution.

Best tests are definately terrestrial in a controlled environment.

There are certain situations where a crop delivers higher resolution than a FF with the same lens (even disregarding DoF, AF and the corners). Roger M. Clark has nice shots of the moon with the 5D2 and the 7D that show this:

www.clarkvision.com/articles/digital.sensor.performance.summary (http://www.clarkvision.com/articles/digital.sensor.performance.summary)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 20, 2013, 12:29:20 PM
Wow, you're a tough crowd to please!

I'm very happy with the results I got. Given how I use my camera, I don't need further testing.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 20, 2013, 01:08:36 PM
There are certain situations where a crop delivers higher resolution than a FF with the same lens (even disregarding DoF, AF and the corners). Roger M. Clark has nice shots of the moon with the 5D2 and the 7D that show this:

www.clarkvision.com/articles/digital.sensor.performance.summary (http://www.clarkvision.com/articles/digital.sensor.performance.summary)

When I wrote, "All else being equal, the larger the format, the better the image quality," there was obviously a bit of shorthand going on. Particularly, to maintain the same field of view with a larger format, you need a longer focal length. Just as you wouldn't compare a P&S with an 8mm lens to a 5DIII with an 8mm lens, you really can't compare a 7D with a 300mm lens to a 5DIII with a 300mm lens -- even if you can physically mount the same lens to both cameras. Rather, you'd compare that P&S with an 8mm lens to a 5DIII with a 50mm lens, and you should compare the 7D with a 300mm lens to a 5DIII with a 500mm lens -- native, in all cases, not with extenders.

And you will, indeed, get substantially better images (with comparable framing) from a 5DIII with a 500mm lens than a 7D with a 300mm lens. That an uncropped image from a 7D with a 300mm lens is superior to a cropped image with a 300mm lens is no more surprising than that slicing away all of an 8x10 negative shot with a 300mm lens but for a 1" x 1.5" rectangle results in a worse image than you'd get from a 135 frame with a 35mm lens.

Once again, all else is clearly not always equal. If all you've got is a 300mm lens and you want to shoot the full disc of the moon, yes, of course, you're going to get better results from that lens with a 7D than a 5DIII. But the guy next to you with a 5DIII and a 1200mm f/5.6 is going to get an image of the moon that puts yours with your 7D to shame. And the guy the next hill over, the one with a 32" Dobsonian? Well....

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Robert Welch on January 20, 2013, 01:11:21 PM
I didn't look at the tests done, as I've been using cropped sensor cameras since 2003 and full frame (& APS-H) cameras since 2007 and can say that generally, the bigger the sensor the better the overall quality of the image. It's not to say that a given combination of APS-C camera with a given lens in a certain situation won't out perform a full frame with a particular lens in the same situation, but in more situations than not you'll probably get the best results from the larger sensor camera. That's why they are still making large sensor cameras, if that wasn't true then the 4/3rds format would have taken over the industry years ago.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Robert Welch on January 20, 2013, 01:18:17 PM
This reminds me a little of the comparisons between medium format and 35mm film. Back in the day I shot both, had a Rolleicord that may have had a focusing problem, always gave me just slightly soft images. I could get better images with my Canon AE-1 using Technical Pan film, ASA (same as ISO) 25, which had super tight grain that could be enlarged up to 16x20 without seeing the grain for the most part. Did that mean that 35mm film cameras were better than medium format? Of course not.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 20, 2013, 01:20:06 PM
At Building Panoramics we recently purchased a 650D as a family camera for my partner. When it arrived we thought it would be interesting to test it against our 5D mk1 and mk2s. Our test was wholly empirical - we shot both cameras at ISO 100, from a sturdy tripod, and used a 50mm 1.4 on the 650 and an 85mm 1.8 on the MK2, both at f8 as this is the aperture we tend to use for buildings. We expected to see a difference.

The first two pictures attached are the whole images, reduced for the web. The third and fourth are the 100% crops.

We could not tell any difference, apart from the DoF. This surprised us as the mk2 was about £2000 when we bought it in 2008, and the 650 cost about a third of that.

So we took the 650D out on assignment with the FFs, and I can say that there is something about the images from the 650 that does not quite have the quality of the 5Ds. Just what this is is difficult to quantify: maybe it's the subtlety of the tonal graduation in difficult areas, I don't know. I don't think there is any difference in the actual sharpness.

Most tests are done at close distances, and as East Wind Photography has suggested, the goal posts move in practical applications where greater distances are involved.

Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 20, 2013, 01:34:35 PM
We could not tell any difference, apart from the DoF.

I'm actually not at all surprised. You even could have equalized the DoF by shooting the 5DII at f/11 and ISO 200.

In good light with good glass at small apertures, you'd have to be printing large and looking very critically to tell the difference.

But in dim light, or if you need to stretch the dynamic range by pulling up the shadows...that's when the 5DII is going to start to pull away. Or if you're making prints bigger than 24" x 36".

And still, poor technique can easily obliterate the differences.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 20, 2013, 03:06:37 PM
Once again, all else is clearly not always equal. If all you've got is a 300mm lens and you want to shoot the full disc of the moon, yes, of course, you're going to get better results from that lens with a 7D than a 5DIII. But the guy next to you with a 5DIII and a 1200mm f/5.6 is going to get an image of the moon that puts yours with your 7D to shame.

300 mm vs. 1200 mm... so now we're talking about lenses, not sensors anymore?   :)

But I agree with you, when comparing FF vs crop it's not only about resolution. It's also about dynamic range, noise, cost, weight etc.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Don Haines on January 20, 2013, 05:24:14 PM
Once again, all else is clearly not always equal. If all you've got is a 300mm lens and you want to shoot the full disc of the moon, yes, of course, you're going to get better results from that lens with a 7D than a 5DIII. But the guy next to you with a 5DIII and a 1200mm f/5.6 is going to get an image of the moon that puts yours with your 7D to shame. And the guy the next hill over, the one with a 32" Dobsonian? Well....

yeah..... but is the guy on the last hill hand-holding the 32" Dobsinian? And if he is, who's going to argue with him?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 20, 2013, 05:57:45 PM
Once again, all else is clearly not always equal. If all you've got is a 300mm lens and you want to shoot the full disc of the moon, yes, of course, you're going to get better results from that lens with a 7D than a 5DIII. But the guy next to you with a 5DIII and a 1200mm f/5.6 is going to get an image of the moon that puts yours with your 7D to shame. And the guy the next hill over, the one with a 32" Dobsonian? Well....

yeah..... but is the guy on the last hill hand-holding the 32" Dobsinian? And if he is, who's going to argue with him?

The <a href="http://hubblesite.org/">gang down south</a> might be able to give him a good run for the money....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 20, 2013, 09:31:18 PM
The bigger the format, the less critical of the lens that's infront of it. That's why my MF film shot with a beat up scratched 85mm 2.8 is sharper than 35mm cameras of the day.

The same holds true with current digital MF and 35mm systems.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 20, 2013, 11:58:16 PM
Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: helpful on January 21, 2013, 12:17:47 AM
Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&

Assuming M.R. means signal to noise ratio by S/N, then he is correct. Actually, the linear resolving power of the lens needs to be increased by the crop factor, and the absolute resolving power of the lens needs to be increased by the square of the crop factor. But this is all based on an imaginary hypothesis, an APS sensor with the exact same S/N ratio as full-frame. Anything is true if the hypothesis itself is false.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 09:42:10 AM
Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&

is it, if the S/N and Mp  is the same from the two sensor areas, then it must be an optical question , and there the APS lenses must be 1,5  1.6 better than the  24x36mm lens.

As I already explained, it is a question of how much enlargement is necessary for a print.

If you're making a 24" x 36" print, the APS-C image will be enlarged 41x from the sensor's original size of 14.8mm x 22.2 mm, but the full-frame will only be enlarged 25x from the sensor's original size of 24mm x 36mm.

Whether you measure S/N in noise per pixel or noise per square mm of sensor, because you've got two and a half times as many square mm of sensor per pixel with the larger format, you're getting that much better of an overall signal to noise ratio.

Imagine you were back in the days of film. You have a 35mm camera loaded with Velveeta on one tripod and an 8x10 view camera loaded with the exact same film on a second tripod. The 35mm camera has a 50mm lens and the view camera has a 400mm lens, both of which give the same normal field of view on the respective cameras.

You'd agree that, since it's the exact same film, the exact same chemistry, that the S/N ratio is exactly the same, right?

Now, let's say we're making an 8" x 10" print from the exposure. The 35mm negative needs to get enlarged 7.5x to make the print, but, for the view camera, it's a contact print.

If you don't agree that the contact print from the view camera will be dramatically sharper and have far less grain than the enlargement from the 35mm camera, then you truly are hopeless.

Now, you might still argue that the pixel dimensions are relevant, but I'll show they're not.

Let's not use traditional printing methods, but rather scan the film. But we want to wind up with the same megapickle files for both, to simulate this contrived example. We're going to scan the 8x10 negate at a lowly 300 ppi, and we're going to scan the 35mm negative at a whopping 2250 ppi. We're still going to make an 8x10 print, and we're going to do it at 300 ppi. And, because of the resolutions I picked, it "just happens" that no interpolation of either file is necessary; both will still print at 300 ppi at 8" x 10".

Once again, if you still don't think that the print from the 300 ppi scan of the view camera's negative will blow away the 2250 ppi scan from the 35mm camera, you're hopeless.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: East Wind Photography on January 21, 2013, 10:06:51 AM
This assumes that you also always print the full frame. For some cropping is always required.  If you crop the same image to the same composition your results may vary.  We don't always have the luxury of filling the frame especially when using a prime lens in less than adequate quarters.

Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&

is it, if the S/N and Mp  is the same from the two sensor areas, then it must be an optical question , and there the APS lenses must be 1,5  1.6 better than the  24x36mm lens.

As I already explained, it is a question of how much enlargement is necessary for a print.

If you're making a 24" x 36" print, the APS-C image will be enlarged 41x from the sensor's original size of 14.8mm x 22.2 mm, but the full-frame will only be enlarged 25x from the sensor's original size of 24mm x 36mm.

Whether you measure S/N in noise per pixel or noise per square mm of sensor, because you've got two and a half times as many square mm of sensor per pixel with the larger format, you're getting that much better of an overall signal to noise ratio.

Imagine you were back in the days of film. You have a 35mm camera loaded with Velveeta on one tripod and an 8x10 view camera loaded with the exact same film on a second tripod. The 35mm camera has a 50mm lens and the view camera has a 400mm lens, both of which give the same normal field of view on the respective cameras.

You'd agree that, since it's the exact same film, the exact same chemistry, that the S/N ratio is exactly the same, right?

Now, let's say we're making an 8" x 10" print from the exposure. The 35mm negative needs to get enlarged 7.5x to make the print, but, for the view camera, it's a contact print.

If you don't agree that the contact print from the view camera will be dramatically sharper and have far less grain than the enlargement from the 35mm camera, then you truly are hopeless.

Now, you might still argue that the pixel dimensions are relevant, but I'll show they're not.

Let's not use traditional printing methods, but rather scan the film. But we want to wind up with the same megapickle files for both, to simulate this contrived example. We're going to scan the 8x10 negate at a lowly 300 ppi, and we're going to scan the 35mm negative at a whopping 2250 ppi. We're still going to make an 8x10 print, and we're going to do it at 300 ppi. And, because of the resolutions I picked, it "just happens" that no interpolation of either file is necessary; both will still print at 300 ppi at 8" x 10".

Once again, if you still don't think that the print from the 300 ppi scan of the view camera's negative will blow away the 2250 ppi scan from the 35mm camera, you're hopeless.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 10:37:51 AM
This assumes that you also always print the full frame. For some cropping is always required.  If you crop the same image to the same composition your results may vary.  We don't always have the luxury of filling the frame especially when using a prime lens in less than adequate quarters.

If you're shooting side-by-side with a 7D and a 20mm prime, a 5DIII and a 35mm prime, and an 8x10 view camera and a 250mm prime, you're going to be cropping away the same proportional amount to get the same composition from each, rendering the cropping point moot.

If you're distance-limited, sure, it can make a difference...but generally not at much as most people tend to think. If that little birdie only fills an eighth of your frame with the 800mm f/5.6 on the 5DIII, you'll get better results putting the lens on the 7D, but not hugely better. The real answer is to improve your tracking skills so you can get closer and fill the frame, with whatever camera / lens combination.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 21, 2013, 11:04:56 AM
Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&

is it, if the S/N and Mp  is the same from the two sensor areas, then it must be an optical question , and there the APS lenses must be 1,5  1.6 better than the  24x36mm lens.

As I already explained, it is a question of how much enlargement is necessary for a print.

If you're making a 24" x 36" print, the APS-C image will be enlarged 41x from the sensor's original size of 14.8mm x 22.2 mm, but the full-frame will only be enlarged 25x from the sensor's original size of 24mm x 36mm.

Whether you measure S/N in noise per pixel or noise per square mm of sensor, because you've got two and a half times as many square mm of sensor per pixel with the larger format, you're getting that much better of an overall signal to noise ratio.

Imagine you were back in the days of film. You have a 35mm camera loaded with Velveeta on one tripod and an 8x10 view camera loaded with the exact same film on a second tripod. The 35mm camera has a 50mm lens and the view camera has a 400mm lens, both of which give the same normal field of view on the respective cameras.

You'd agree that, since it's the exact same film, the exact same chemistry, that the S/N ratio is exactly the same, right?

Now, let's say we're making an 8" x 10" print from the exposure. The 35mm negative needs to get enlarged 7.5x to make the print, but, for the view camera, it's a contact print.

If you don't agree that the contact print from the view camera will be dramatically sharper and have far less grain than the enlargement from the 35mm camera, then you truly are hopeless.

Now, you might still argue that the pixel dimensions are relevant, but I'll show they're not.

Let's not use traditional printing methods, but rather scan the film. But we want to wind up with the same megapickle files for both, to simulate this contrived example. We're going to scan the 8x10 negate at a lowly 300 ppi, and we're going to scan the 35mm negative at a whopping 2250 ppi. We're still going to make an 8x10 print, and we're going to do it at 300 ppi. And, because of the resolutions I picked, it "just happens" that no interpolation of either file is necessary; both will still print at 300 ppi at 8" x 10".

Once again, if you still don't think that the print from the 300 ppi scan of the view camera's negative will blow away the 2250 ppi scan from the 35mm camera, you're hopeless.

Cheers,

b&

I think S/N based on area (where number of photons captured per unit time is proportional to area) varies fundamentally as the square root of ratio of areas. So increasing area by 2.5x improves S/N only by 1.6x. (I do know other factors do come in, but the basic statistics of S/N is a sqrt relationship).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: klickflip on January 21, 2013, 11:17:44 AM
Thanks an really interesting test. As you've managed to show that there really isn't much difference comparing 2000px wide Jpgs that show some compression.
If thats all your images are ever going to be finalised as and viewed on screen at 50% then the 650 will be just great.

However... The view selected isn't the best for a proper test I think. Try subjects with smooth tones and darker gradients plus interesting detail and then you'll see the noise & sharpness when especially viewing or working on them in RAW or at least tiffs in photoshop viewed 200%.
Try some nicely lit portraits or some well composed architecture and there will be a big difference.

But its horses for courses really, if you're just going be shooting what we might call messy scenes like this and kids running around and holiday pics then it might not well be distinguishable to FF instantly.

More than anything  it will them more come down to your technique to get the best out of FF, framing, catching beautiful light and the moment together whilst selecting the 'optimum' shutter / aperture, iso and lens plus raw/post processing which can make a huge difference to noise & sharpness plus the grade to push a feel which can be more important than anything.

A good photographer can make APS-C look like FF or MFDB and a bad photographer can make FF look like P&S.

And the previous post that mentioned what about cropping.. well if you are constantly cropping your FF that much then
you shouldn't have FF or a DSLR in my eyes anyway ;)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 11:28:01 AM
I think S/N based on area (where number of photons captured per unit time is proportional to area) varies fundamentally as the square root of ratio of areas. So increasing area by 2.5x improves S/N only by 1.6x. (I do know other factors do come in, but the basic statistics of S/N is a sqrt relationship).

You're correct about the actual numbers, of course. I didn't mean to imply a specific numerical relationship, which is why I tried to phrase it as loosely as I did.

With each standard increase in format, you gain an effective (roughly) one stop of ISO performance. If you're happy with ISO 400 on 4/3, you'll be happy with ISO 800 on APS-C, and with ISO 1600 on full frame, and ISO 3200 on medium format -- with a big, honkin' caveat that different manufacturers are using different technologies with their sensors in each segment. In the real world, it's more like ISO 100 on APS-C has half the noise as ISO 100 on 4/3, and so on...your MF back might not actually do all that well at ISO 3200, but its ISO 200 will be at least as clean as ISO 100 on full frame.

And, of course, we're also talking about actual prints, not pixel peeping or other meaningless measures.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 11:55:34 AM
"As I already explained, it is a question of how much enlargement is necessary for a print."

this is about pixels, no film, as long you have 1,6 times better lenses and use f8  and the signal/noise is equal
from the  APS 24 mp  and the  24 mp 24x36 there is no enlargements advantages with 24x36
It is a pure optical question= we need 1,6 better lenses on the APS

Mikael, if what you wrote were true, then a 4000 ppi, 22 megapickle scan of a 35mm negative would produce just as good an 8" x 10" print as a 500 ppi, 20 megapickle scan of an 8" x 10" negative from a view camera. Or, that a 5DIII would make as good a print as a 20 megapickle 8x10 view camera back.

It would also mean that this 18 megapickle toy:

http://www.amazon.com/Cybersnap-1018-Micro-Digital-Camera/dp/B007PVMKPU/ref=sr_1_35?s=photo&ie=UTF8&qid=1358787121&sr=1-35 (http://www.amazon.com/Cybersnap-1018-Micro-Digital-Camera/dp/B007PVMKPU/ref=sr_1_35?s=photo&ie=UTF8&qid=1358787121&sr=1-35)

would beat the pants off of the original 1Ds with its wimpy 11 megapickles.

And that assertion is so laughably idiotic that there's no point in further discussion with you.

Seriously, dude. Get a clue. You're in more need of one than any I've seen here in a looooooooong time.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 21, 2013, 12:21:36 PM
I have been using a 7D for 3 years for bird photography and earlier this month I bought a 5D III, with which I am absolutely delighted. But, the old 7D can hold its own at the limits of resolution. This is not scientific as only two photos are compared under slightly different conditions, but they do illustrate the advantages of pixel density at 100% crops for fine detail. Both were in raw, 100% crops and with the 300mm f/2.8 II + 2xTC at f/8. The 7D was at iso 320 and /1250, the 5D III at 800 and 1/500 (so same amount of light but the 7D was given an iso advantage). The 7D shot is less pixillated (1332x1218 vs 809x726) and there is slihgtly better resolution of the feathers on the back. Last night, I took a snow scene lit by lamplight at 1/40 sec and iso 12,800 with the 5D III - I couldn't have done this on on the 7D. It's horses for courses.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 12:35:44 PM
The 7D shot is less pixillated (1332x1218 vs 809x726) and there is slihgtly better resolution of the feathers on the back.

The 5DIII shot is also a bit underexposed, which isn't doing it any good. Indeed, the loss of IQ because of that underexposure is roughly comparable to the resolution gain of the 7D.

The two are close enough that I wouldn't make the decision of which camera to pick up based on raw resolution. Instead, I'd go with the 5DIII for its superior autofocus performance -- and, presumably, for the not-yet-real 7DII for its autofocus equal to the 5DIII but higher resolution and faster framerate. But I still might pick a 1DX instead of either, despite its lower pixel density, for its superior metering ability plus its even marginally better autofocus performance plus its absolutely insane framerate.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: NormanBates on January 21, 2013, 12:54:43 PM
Indeed, film is different, it's as if you were comparing a 18 mpix APS-C sensor with a 50 mpix fullframe sensor.
My test is of that which is relevant to me: close to 20 mpix on both

Also, my test is of that which is relevant to me, which means it's basically useles for birding fans
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 21, 2013, 12:57:32 PM
Indeed, film is different, it's as if you were comparing a 18 mpix APS-C sensor with a 50 mpix fullframe sensor.
My test is of that which is relevant to me: close to 20 mpix on both

Also, my test is of that which is relevant to me, which means it's basically useles for birding fans
.

Just saw your tests, Nice job. FF takes a wet dump on APS-C for sharpness, and MF would do the same for FF 35mm.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 21, 2013, 01:30:21 PM
The 7D shot is less pixillated (1332x1218 vs 809x726) and there is slihgtly better resolution of the feathers on the back.

The 5DIII shot is also a bit underexposed, which isn't doing it any good. Indeed, the loss of IQ because of that underexposure is roughly comparable to the resolution gain of the 7D.

The two are close enough that I wouldn't make the decision of which camera to pick up based on raw resolution. Instead, I'd go with the 5DIII for its superior autofocus performance -- and, presumably, for the not-yet-real 7DII for its autofocus equal to the 5DIII but higher resolution and faster framerate. But I still might pick a 1DX instead of either, despite its lower pixel density, for its superior metering ability plus its even marginally better autofocus performance plus its absolutely insane framerate.

Cheers,

b&

I had made a decision to buy the 5D III, it is a phenomenal piece of kit and, most importantly with incredible autofocus consistency. The 7D is 3 years older technology. I showed those shots to show that even with outdated technology, pixel density can be important - I am not arguing to buy a 7D. We'll see what a more modern APS-C can do if ever the 7D II arrives.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 01:37:07 PM
"As I already explained, it is a question of how much enlargement is necessary for a print."

this is about pixels, no film there you are enlarging grain etc , as long you have 1,6 times better lenses and use f8  and the signal/noise is equal from the  APS 24 mp  and the  24 mp 24x36 there is no enlargements advantages with 24x36
It is a pure optical question= we need 1,6 better lenses on the APS

Whoa !! Come on guys, Mikael is right here. I'm amazed how many people still confuse format with digital image size. It must be all us old gits who come from film.

To use 18 MP as example, 18MP of digital info is 18MP - it doesn't matter what format it's in ! A 5D mk1 file has to be "enlarged" more than that from a 7D. Talking of enlarging an APS file "40" times is wrong - who ever said that does not understand what is happening to enable them to view this digital data as a picture. Enlarge an APS Film negative 40 times - yes.

I'm surprised Neuro hasn't jumped in and put that one straight !

Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 21, 2013, 01:59:51 PM
"As I already explained, it is a question of how much enlargement is necessary for a print."

this is about pixels, no film there you are enlarging grain etc , as long you have 1,6 times better lenses and use f8  and the signal/noise is equal from the  APS 24 mp  and the  24 mp 24x36 there is no enlargements advantages with 24x36
It is a pure optical question= we need 1,6 better lenses on the APS

Whoa !! Come on guys, Mikael is right here. I'm amazed how many people still confuse format with digital image size. It must all us old gits who come from film.

To use 18 MP as example, 18MP of digital info is 18MP - it doesn't matter what format it's in ! A 5D mk1 file has to be "enlarged" more than that from a 7D. Talking of enlarging an APS file "40" times is rubbish - who ever said that does not understand what is happening to enable them to view this digital data as a picture. Enlarge an APS Film negative 40 times - yes.

I'm surprised Neuro hasn't jumped in and put that one straight !
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference. But we are far from perfection, and as lots of this process is analogue, we never will reach digital perfection. Any two sensors of the same tech generation of different sizes will have very different characteristics. The smaller sensor, even if it has the same number of MP (such as a 7D vs a 1D X) will inevitably have smaller individual pixels, each able to gather less light than their FF equivalent and require more amplification to get the same rated sensitivities. This extra amplification of a weaker signal leads to more noise.

Just as adding MP to any one sensor doesn't harm as the final image is the sum total of all the pixels (the entire sensor), the larger sensor will always have an overall advantage - the larger sensor as a whole is able to capture more light. In that way, the analogy of two different size cuts from the same film (read same tech generation) is spot on. The larger one will always win.

Since sensors reached about 10+ MP, magnification of the sensor became much more important than how big each individual pixel is printed. If not, a Nokia Pureview 808 would be better than all but the latest medium format digital backs.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 02:12:23 PM
"As I already explained, it is a question of how much enlargement is necessary for a print."

this is about pixels, no film there you are enlarging grain etc , as long you have 1,6 times better lenses and use f8  and the signal/noise is equal from the  APS 24 mp  and the  24 mp 24x36 there is no enlargements advantages with 24x36
It is a pure optical question= we need 1,6 better lenses on the APS

Whoa !! Come on guys, Mikael is right here. I'm amazed how many people still confuse format with digital image size. It must all us old gits who come from film.

To use 18 MP as example, 18MP of digital info is 18MP - it doesn't matter what format it's in ! A 5D mk1 file has to be "enlarged" more than that from a 7D. Talking of enlarging an APS file "40" times is rubbish - who ever said that does not understand what is happening to enable them to view this digital data as a picture. Enlarge an APS Film negative 40 times - yes.

I'm surprised Neuro hasn't jumped in and put that one straight !
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference. But we are far from perfection, and as lots of this process is analogue, we never will reach digital perfection. Any two sensors of the same tech generation of different sizes will have very different characteristics. The smaller sensor, even if it has the same number of MP (such as a 7D vs a 1D X) will inevitably have smaller individual pixels, each able to gather less light than their FF equivalent and require more amplification to get the same rated sensitivities. This extra amplification of a weaker signal leads to more noise.

Just as adding MP to any one sensor doesn't harm as the final image is the sum total of all the pixels (the entire sensor), the larger sensor will always have an overall advantage - the larger sensor as a whole is able to capture more light. In that way, the analogy of two different size cuts from the same film (read same tech generation) is spot on. The larger one will always win.

Since sensors reached about 10+ MP, magnification of the sensor became much more important than how big each individual pixel is printed. If not, a Nokia Pureview 808 would be better than all but the latest medium format digital backs.

What you say is correct, but the enlargement required to produce a given picture size from a 7D and a 1DX is the same, irrespective of whether the resulting picture from the 1DX is better or not.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 02:29:29 PM
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference.

Eh, no.

Not even close.

Camera A has a square sensor, 1" x 1". Camera B has a square sensor, 2" x 2". Both cameras have a 1024-by-1024 pixel array, for a grand total of one megapickle. Both sensors are digital nirvana, counting photons at the very limit of what quantum mechanics allows.

Each of camera B's pixels can gather four times as many photons as camera A's pixels. Camera B has two stops more dynamic range and the gradients it captures are two stops smoother, with two stops less pixelation. Make a 2" x 2" print from both, and the one from camera B will show two stops more detail and appear that much sharper.

Still not convinced?

Imagine that the sensors are so small and so densely packed that a single photon is enough to fill one of camera a's pixel wells. It can only record black and white, but it does so at amazingly high resolution. Camera B's pixels, on the other hand, are twice the linear dimension, so each photosite can record the presence of 0, 1, 2, 3, or 4 photons. The end result for camera A is a 1 megapickle black and white image; the end result for camera B is a 1 megapickle four-bit grayscale image. Obviously, camera B's image contains a great deal more information -- and it looks it, too.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 21, 2013, 02:33:30 PM
"As I already explained, it is a question of how much enlargement is necessary for a print."

this is about pixels, no film there you are enlarging grain etc , as long you have 1,6 times better lenses and use f8  and the signal/noise is equal from the  APS 24 mp  and the  24 mp 24x36 there is no enlargements advantages with 24x36
It is a pure optical question= we need 1,6 better lenses on the APS

Whoa !! Come on guys, Mikael is right here. I'm amazed how many people still confuse format with digital image size. It must all us old gits who come from film.

To use 18 MP as example, 18MP of digital info is 18MP - it doesn't matter what format it's in ! A 5D mk1 file has to be "enlarged" more than that from a 7D. Talking of enlarging an APS file "40" times is rubbish - who ever said that does not understand what is happening to enable them to view this digital data as a picture. Enlarge an APS Film negative 40 times - yes.

I'm surprised Neuro hasn't jumped in and put that one straight !
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference. But we are far from perfection, and as lots of this process is analogue, we never will reach digital perfection. Any two sensors of the same tech generation of different sizes will have very different characteristics. The smaller sensor, even if it has the same number of MP (such as a 7D vs a 1D X) will inevitably have smaller individual pixels, each able to gather less light than their FF equivalent and require more amplification to get the same rated sensitivities. This extra amplification of a weaker signal leads to more noise.

Just as adding MP to any one sensor doesn't harm as the final image is the sum total of all the pixels (the entire sensor), the larger sensor will always have an overall advantage - the larger sensor as a whole is able to capture more light. In that way, the analogy of two different size cuts from the same film (read same tech generation) is spot on. The larger one will always win.

Since sensors reached about 10+ MP, magnification of the sensor became much more important than how big each individual pixel is printed. If not, a Nokia Pureview 808 would be better than all but the latest medium format digital backs.

What you say is correct, but the enlargement required to produce a given picture size from a 7D and a 1DX is the same, irrespective of whether the resulting picture from the 1DX is better or not.
It depends upon whether you're talking about enlargement of each digital pixel in the file, or enlargement of the sensor/film. Enlargement of the sensor (with any moderately large MP sensor) is much more closely linked to image quality than enlargement of the digital file.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 21, 2013, 02:36:16 PM
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference.

Eh, no.

Not even close.

Camera A has a square sensor, 1" x 1". Camera B has a square sensor, 2" x 2". Both cameras have a 1024-by-1024 pixel array, for a grand total of one megapickle. Both sensors are digital nirvana, counting photons at the very limit of what quantum mechanics allows.

Each of camera B's pixels can gather four times as many photons as camera A's pixels. Camera B has two stops more dynamic range and the gradients it captures are two stops smoother, with two stops less pixelation. Make a 2" x 2" print from both, and the one from camera B will show two stops more detail and appear that much sharper.

Still not convinced?

Imagine that the sensors are so small and so densely packed that a single photon is enough to fill one of camera a's pixel wells. It can only record black and white, but it does so at amazingly high resolution. Camera B's pixels, on the other hand, are twice the linear dimension, so each photosite can record the presence of 0, 1, 2, 3, or 4 photons. The end result for camera A is a 1 megapickle black and white image; the end result for camera B is a 1 megapickle four-bit grayscale image. Obviously, camera B's image contains a great deal more information -- and it looks it, too.

Cheers,

b&
I fully agree with you. That's why I followed that first sentence with 'But we are far from perfection, and as lots of this process is analogue, we never will reach digital perfection', and then went on to say 'the larger sensor as a whole is able to capture more light'
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 21, 2013, 03:33:35 PM
Mikael, I've explained enlargement multiple times.

But I'll give it yet another whack. Why not?

Let's say your client has hired you to photograph his sailboat tied to the dock at sunset, and he wants you to make a 48" x 72" print.

If you use a 135 format camera, such as a 5DIII, the image recorded on the sensor will have to be enlarged roughly 50 times to make said print. If you use an 8x10 view camera, the image will be enlarged about 6 times.

Let's say your view camera has a low-resolution sensor that is all of 500 ppi, making it an effective 20 megapickles -- slightly less than the 5DIII's 22 megapickles.

Also assume you're using a 50mm lens on the 5DIII and a 400mm lens, so both have the same field of view. And assume you're shooting the 5DIII at f/8 and the view camera at f/64, so they both have the same depth of field. And even go ahead and assume that you're shooting the 5DIII at ISO 100 and the view camera at ISO 6400, so the shutter speed is the same. For the sake of this discussion, also assume that the technology is comparable for both -- the sensors are the same generation, the lenses are both superb, and so on.

So, two setups almost identical. On the one hand, we've got a 22 megapickle 5DIII at ISO 100; on the other, a 20 megapickle view camera at ISO 6400. Same depth of field, same shutter speed, same framing, same everything else. And, at the end of the day, the same 48" x 72" print.

What, if any, difference do you think there will be between the two prints, and why?

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 21, 2013, 03:41:10 PM
If we're talking about two cameras, both with 18MP of digital perfection, then presuming each has a lens up to the demands of the sensor, there will be no difference.

Eh, no.

Not even close.

Camera A has a square sensor, 1" x 1". Camera B has a square sensor, 2" x 2". Both cameras have a 1024-by-1024 pixel array, for a grand total of one megapickle. Both sensors are digital nirvana, counting photons at the very limit of what quantum mechanics allows.

Each of camera B's pixels can gather four times as many photons as camera A's pixels. Camera B has two stops more dynamic range and the gradients it captures are two stops smoother, with two stops less pixelation. Make a 2" x 2" print from both, and the one from camera B will show two stops more detail and appear that much sharper.

Sure, but you are not always dynamic range limited, for instance in a studio or in a foggy landscape situation. The only difference will be that camera B's sensor needs four times less exposure (and even that doesn't matter when using lighting or a tripod).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 03:55:35 PM
Well I know Im not the Fiery Finn, but here goes:

The enlargement required to produce the prints would be similar, the 10x8 would require slightly more "enlargement" because it's less megapixel.

You're shooting the view camera at f64, not sure how the very large pixels on this hypothetical 10x8 sensor would negate the diffraction of this aperture. Similarly in this theoretical scenario the light capturing ability of this sensor will be amazing.

However you've wacked the ISO up to 6400 on the view camera. Again will the very large pixels cope with this - we don't know.

Actually just thinking about this as I go along, you actually cannot say what the difference will be, apart from the fact the enlargement is about the same, because of the very small aperture and very high ISO being used on the theoretical view camera.

IF the very large pixels resulted in no more diffraction than f8 on the 5D, and IF iso 6400 resulted in no more noise etc, then the image from the view camera would exhibit smoother tones, smoother graduation and more perceived resolution due to the lens projecting light in a much larger image onto the 10 x 8 chip.

Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 21, 2013, 03:59:30 PM
Let me have a stab at this, as I don’t mind making a mistake of I can learn from it. The 50 mm lens at f/8 has exactly the same open aperture as a 400 mm at f/64. Therefore, both let in the same number of photons at the same shutter speed. These are spread over the same number of pixels for each sensor. Therefore the signal to noise is the same for both sensors as both follow the square root of the number of photons. Each final enlargement has the same number of pixels. So each final enlargement has the same number of pixels with same signal to noise. So, they are of identical quality, the lenses being of equal quality..
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 04:20:29 PM
Some of you are confusing enlargement and sensor resolution.  Do you know who you are?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 04:38:17 PM
Some of you are confusing enlargement and sensor resolution.  Do you know who you are?

As digital sensor potential resolution is physically defined by pixels, enlargement is indubitably related to sensor resolution.

This is totally different to film, where the image recorded on the film emulsion was physically enlarged to whatever size you were printing. ( or projecting ).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 04:44:22 PM
Some of you are confusing enlargement and sensor resolution.  Do you know who you are?

well it is a optical question and it is hard to get a APS lens that are 1,6 times better than a 24x36mm lens regarding resolution, contrast etc. If  there was one there will  not be any differences results wise between a 24MP APS sensor and a 24Mp 24x36mm sensor and if the signal/noise ratio was the same from the two sensors

What exactly do you mean by an "APS lens that is 1.6 times better than 24x36mm lens"?  Are you talking about two different lenses (e.g. an EF-S lens and an EF lens) or the same lens on different bodies?

Under what circumstances do you suppose the SNR would be the same for an APS-C sensor and a FF sensor that each had the same number of pixels?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 04:50:36 PM
Some of you are confusing enlargement and sensor resolution.  Do you know who you are?

As digital sensor potential resolution is physically defined by pixels, enlargement is indubitably related to sensor resolution.

This is totally different to film, where the image recorded on the film emulsion was physically enlarged to whatever size you were printing. ( or projecting ).

What makes it so different?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 05:06:36 PM
You are not physically enlarging each pixel from your sensor. The pixels are the electronic capture devices. This information is then interpreted by your computer program. Enlarging them to see your picture would be about as useful as enlarging the processor in your computer and having a look at that.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 05:17:37 PM
You are not physically enlarging each pixel from your sensor. The pixels are the electronic capture devices. This information is then interpreted by your computer program. Enlarging them to see your picture would be about as useful as enlarging the processor in your computer and having a look at that.

Are you talking about the sensor or the image?  ???
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 21, 2013, 05:21:47 PM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 21, 2013, 05:45:43 PM
Mikael, I've explained enlargement multiple times.

But I'll give it yet another whack. Why not?

Let's say your client has hired you to photograph his sailboat tied to the dock at sunset, and he wants you to make a 48" x 72" print.

If you use a 135 format camera, such as a 5DIII, the image recorded on the sensor will have to be enlarged roughly 50 times to make said print. If you use an 8x10 view camera, the image will be enlarged about 6 times.

Let's say your view camera has a low-resolution sensor that is all of 500 ppi, making it an effective 20 megapickles -- slightly less than the 5DIII's 22 megapickles.

Also assume you're using a 50mm lens on the 5DIII and a 400mm lens, so both have the same field of view. And assume you're shooting the 5DIII at f/8 and the view camera at f/64, so they both have the same depth of field. And even go ahead and assume that you're shooting the 5DIII at ISO 100 and the view camera at ISO 6400, so the shutter speed is the same. For the sake of this discussion, also assume that the technology is comparable for both -- the sensors are the same generation, the lenses are both superb, and so on.

So, two setups almost identical. On the one hand, we've got a 22 megapickle 5DIII at ISO 100; on the other, a 20 megapickle view camera at ISO 6400. Same depth of field, same shutter speed, same framing, same everything else. And, at the end of the day, the same 48" x 72" print.

What, if any, difference do you think there will be between the two prints, and why?

Cheers,

b&

Why are you writing about 50mm lens , 500 PPI  etc etc etc. it has nothing to do with the question
I have answered , and it started here http://www.canonrumors.com/forum/index.php?topic=12448.15 (http://www.canonrumors.com/forum/index.php?topic=12448.15)
it is all about the optical resolution, a  optical issue with the given parameters I presented - and that I have wrote more than once here.

Explain now the enlargement factor  with the given parameters I have presented since http://www.canonrumors.com/forum/index.php?topic=12448.15 (http://www.canonrumors.com/forum/index.php?topic=12448.15) .
and please, keep your self to the subject.

and cheers/skål

From my viewpoint, APS-C delivers me from both teleconverters and high fstops on many occasions.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 06:26:00 PM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?

Why would you answer with a question?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Don Haines on January 21, 2013, 06:49:00 PM
good gravy people..... there is no practical answer to the question... cameras are systems.... it's not just the sensor.... You have sensors, lenses, and software. In theory, a simillarly designed lens of the appropriate focal length, F stop, shutter, materials, and build for APS-C and one for FF, should act the same..... but good luck finding a pair. Every model of camera will have different algorithms..... with different processor speeds and different features there are different demands on the camera and also, software gets optimized and bugs get fixed.... good luck finding two camera models that run the same software. Sensors are constantly evolving.... for the comparison to be meaningful they would have to be built with the same age of technology.

And assuming you were able to find find two truly comparable systems, just what do you mean by sharpness?
Are you talking sharpness of a pixel, sharpness of an image, or sharpness per mm of sensor? These are going to give you three different answers. If you are talking about sharpness per mm of sensor my iPad beats any FF or APS-C sensor hands down.... An argument without defined parameters is just an exercise in frustration and hurt feelings.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TheSuede on January 21, 2013, 07:23:46 PM
Full frame isn't sharper than APS, that's basically a metaphorical question. The edges of the naturalization of the silicon surface are treated the same, so it's just as easy to get paper cuts from handling a naked APS sensor edge as an FF sensor edge. I know from personal experience... :)

And this magnification discussion is rather confused, let's just go through the entire image process chain:

1) Reality (in glorious smello-vision 3D!) :)
2) Optical projection 3D >> 2D
3) We digitize that 2D projection into a "pixel resolution" - in this case via a digital camera sensor
4) this "resolution" is presented - either on screen or on print.

Comparing two different camera formats means that we need to change some stuff to equalize points 2) and 3). We want to keep 1) and 4) constant! The reality (model, object, scene) is the same, we want the end result image to be the same.

We need to change the inter-operation scales. We use lower object magnifications - a shorter focal length - in step 2>3. The image pixel is unitless, just a datapoint in the grid of data that makes a digital image. To keep the quality of the intermediate digital image (3) constant, we need to keep per-pixel sharpness and noise constant.

Using the same lens at the same aperture on both systems won't make that happen. Optical defects spread over more pixels in the smaller sensor - since those pixels are physically smaller. But the object resolution - how much detail on the target that you can see - can never get worse with smaller pixels, it can only get better. This is the crop effect birders are after. Target resolution.

Using a 1.5x shorter lens at the same aperture value on the smaller system will make the field of view the same, but DoF will be deeper (more about this later!). Now if the lens is also 1.5x sharper, has the same MTF at 45lp/mm as the larger lens has at 30lp/mm, object resolution will be equal - and since a pixel is a pixel is a pixel, digitized image resolution will also be equal. But noise will be stronger (due to the deeper DoF!).

To get noise equal too, you need to keep the amount of captured light energy equal. And to get the light throughput per second equal, we need to have the same entry pupil diameter on both systems. The entry pupil is what "gathers light" from from the scene from the optical system's point of view - if light is to reach the sensor, it has to pass through this aperture. The nominal entry pupil is focal length divided by f/# - that's why it's named an F-stop.
Small "f" for focal length, and the hash-tag "#" sign signifies unitless result. A 50mm F2.0 then has a nominal 50mm/2.0 = 25mm front pupil. To get the same field of view on APS we need a ~35mm lens. We still need a 25mm front pupil, so the F-stop needs to be 35mm(f) / 25mm(d) = 1.4(#) = F1.4

So if you could make a 35F1.4 that's 1.5x sharper than a 50F2.0, everything would be fine. But that's the problem - that's a very hard thing to do. AND you'd need an APS camera with 1.5^2 = 2.25x lower base ISO to keep light energy storage capacity the same, since ISO is area based.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TheSuede on January 21, 2013, 07:28:53 PM
good gravy people..... there is no practical answer to the question... cameras are systems.... it's not just the sensor.... You have sensors, lenses, and software. In theory, a simillarly designed lens of the appropriate focal length, F stop, shutter, materials, and build for APS-C and one for FF, should act the same..... but good luck finding a pair. Every model of camera will have different algorithms.....
(.../some shortening applied/...)
And assuming you were able to find find two truly comparable systems, just what do you mean by sharpness?
Are you talking sharpness of a pixel, sharpness of an image, or sharpness per mm of sensor? These are going to give you three different answers. If you are talking about sharpness per mm of sensor my iPad beats any FF or APS-C sensor hands down.... An argument without defined parameters is just an exercise in frustration and hurt feelings.

This is the practical, sane and pragmatic answer. I whole-heartedly agree :)

It's up to each and every one for themselves to find the SYSTEM that suits their needs.
For me that "best answer" is sometimes APS, sometimes 1" sensors and sometimes also digital medium format (though that need has fallen drastically the latest three or four years, since the arrival of 20MP+ FF cameras).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 21, 2013, 07:29:52 PM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?

Why would you answer with a question?

Socrates used to.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: East Wind Photography on January 21, 2013, 08:17:57 PM
Nope that's not what I'm seeing comparing the same shots between a 5D3 and a 7D.  The 5D3 cropped to the same size as the 7D resolves a tad more detail in RAW comparisons.  I dont even use the 7D anymore.

This assumes that you also always print the full frame. For some cropping is always required.  If you crop the same image to the same composition your results may vary.  We don't always have the luxury of filling the frame especially when using a prime lens in less than adequate quarters.

If you're shooting side-by-side with a 7D and a 20mm prime, a 5DIII and a 35mm prime, and an 8x10 view camera and a 250mm prime, you're going to be cropping away the same proportional amount to get the same composition from each, rendering the cropping point moot.

If you're distance-limited, sure, it can make a difference...but generally not at much as most people tend to think. If that little birdie only fills an eighth of your frame with the 800mm f/5.6 on the 5DIII, you'll get better results putting the lens on the 7D, but not hugely better. The real answer is to improve your tracking skills so you can get closer and fill the frame, with whatever camera / lens combination.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Don Haines on January 21, 2013, 08:46:09 PM

it does until Canon brings out a  24x36 camera with high pixel density then you can crop as it suits you

yes, but if you built an APS-c sensor at the same pixel density as the sensor in an Ipad you could have an 216Mpixel sensor......
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 21, 2013, 09:11:29 PM
APS-C solves a lot of problems full frame creates...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 09:18:18 PM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?

Why would you answer with a question?

Socrates used to.

Socrates gets some leeway.  People who make unclear or unsubstantiated statements aren't generally afforded the luxury of evading questions in that fashion.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 09:26:58 PM
Some of you are confusing enlargement and sensor resolution.  Do you know who you are?

well it is a optical question and it is hard to get a APS lens that are 1,6 times better than a 24x36mm lens regarding resolution, contrast etc. If  there was one there will  not be any differences results wise between a 24MP APS sensor and a 24Mp 24x36mm sensor and if the signal/noise ratio was the same from the two sensors

What exactly do you mean by an "APS lens that is 1.6 times better than 24x36mm lens"?  Are you talking about two different lenses (e.g. an EF-S lens and an EF lens) or the same lens on different bodies?

Under what circumstances do you suppose the SNR would be the same for an APS-C sensor and a FF sensor that each had the same number of pixels?
please read again what Im saying. I do not suppose anything.I describe parameters who must be alike to compare the different sensors, and what kind of qualities the lens for the APS size must have if we are comparing the two sensor sizes and resolution/contrast.
and please  also read The Suedes answer if you wonder something

I have read your comments and the Suede's comments and I find them confusing.  Hence I asked questions in hopes of being enlightened and all I get is defensiveness and avoidance.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: serendipidy on January 21, 2013, 09:48:10 PM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?

Why would you answer with a question?



Socrates used to.

Look where that got him :o
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Meh on January 21, 2013, 09:49:02 PM
what is it you are wondering about?
And let me tell you that my english is not the best  in the world, but I try.

For one, I asked you what exactly you meant by "the APS-C lens has to be better than the FF lens"?

I followedd that up with a clarifying question asking if you were talking about two different lenses such as one EF-S lens and one EF lens.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 22, 2013, 03:27:24 AM
Well if I can answer with a question. When you look at your picture at 100% on your computer do you think you are looking at the pixels from your sensor ?

Why would you answer with a question?

Socrates used to.

Socrates gets some leeway.  People who make unclear or unsubstantiated statements aren't generally afforded the luxury of evading questions in that fashion.

I can see where you are coming from in terms of the image projected onto a larger sensor is larger. This is where the potential improvements in IQ come from, and I suppose is the basis of this whole thread. An image that is recorded at a larger level has the potential to record more detail given the limitation of lenses and pixels. This is where Mikael is coming from. It's simple physics. However it is wrong to believe that the data from a smaller sensor has to be "enlarged" or "blown up" more than a larger one of equal digital capacity. The image you will see in pixels created by your computer program is the same size from an 18MP 7D as it is from an 18MP 1DX. The pixels created by your computer program, using the information recorded by the camera chip, are the same size for each camera, irrespective of how big or small the original pixels were on the chip.

I have understood from your previous posts that you believe that in order to achieve a digital picture of a given size you have to enlarge each pixel from your sensor until you have the image size you require. 

That's plain wrong - there's nothing to substantiate !

 
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: al-toidz photography on January 22, 2013, 05:03:05 AM
You guys are wasting your time with this pixel peeping bullshit and sensor S____ that you guys are talking about. First, not because you have a full frame sensor does not mean that you can produce a better picture than someone that has APSC size sensor. Second, lens matters. Even if you have full frame camera but has only a mediocre lens in front of the sensor, the resulting image is not as good as let's say, a T2i with 85mm 1.2L or a 70-200 IS II. And lastly, if you are really a good photographer if not great, then any of this camera and lens S____, will mean nothing to you. What do I mean by this? There's a lot of ingredients that involves in photography more than just a camera and a lens. One does not make a good photo just because he/she has the top of the line camera and lens.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plainsman on January 22, 2013, 06:48:12 AM
If you can get close enough to your subject with a 36x24 sensor camera to fill the viewfinder then FF camera is to be preferred. If the image is small in frame with lots of cropping eg aircraft in flight or BIF then the APS-C format is just as good. There are other considerations of course such as pixel size, lens quality etc etc.

In film days the bigger the format the better eg my Mamiya 645 (56x42mm neg size) always beat Nikon/Canon SLR (36x24mm neg size) - for quality large prints - and a Pentax 6x7 (70x56mm neg size) would always beat a Mamiya 645 etc  The same analogy applies to digital.

I suspect that in the long term the APS-C format may disappear - but maybe not!
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 22, 2013, 06:51:32 AM
There is a famous old New Yorker cartoon with one professor saying to another: "The reason why university politics is so bitter is because the stakes are so small.". Substitute 'photographer' for professor and 'FF vs crop debate' for university politics................
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: yablonsky on January 22, 2013, 06:54:23 AM
Nope that's not what I'm seeing comparing the same shots between a 5D3 and a 7D.  The 5D3 cropped to the same size as the 7D resolves a tad more detail in RAW comparisons.  I dont even use the 7D anymore.

Right.

I used the same lenses on the 50D and later on the 5D2 (RAW). 100% crops from the APS-C could not be used.
The image looks like scrambled pixels. Now with the 5D2 the 100% crops are great. A lot of detail and tack sharp.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: p666 on January 22, 2013, 07:53:21 AM
Images talk much better than words when you are talking about photography. I decided to test it myself, and took my 60D, and 5D Mark II, and attached the same 35mm prime lens, and took the same shot. The 5D image of 5616 x 3744 I cropped to 1.6, which gave me 3510 x 2340. I then downsampled the 60D image to the same size, and took a 100% crop of both for screen.

Look very similar to me other than the slight DOF differences, so in terms of image quality really there is no advantage whatsoever in the "crop" sensor, other than having to manually crop the image on FF to get that special "crop factor" you get by default.

The 60D:

(http://farm9.staticflickr.com/8053/8404460677_c85ddb9b8c_b.jpg) (http://www.flickr.com/photos/gman76/8404460677/)

The 5D Mk2:

(http://farm9.staticflickr.com/8096/8404460549_17e44035ed_b.jpg) (http://www.flickr.com/photos/gman76/8404460549/)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 22, 2013, 08:54:59 AM
I suspect that in the long term the APS-C format may disappear - but maybe not!

Canon doesn't think so, they just came up with the M mount which can only be used for APS-C. APS-C has it's advantages, like less size and weight, which is a plus for traveling or photojournalism (supposing one doesn't want to do very large prints).

But indeed, I would also not be surprised when they will stop releasing EF-S mount cameras and lenses in 10 years or so.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 22, 2013, 09:00:38 AM
If we were stuck with 35mm and APS-C film, you would have a point.

We're not. We have sharpening settings in camera, and multiple sharpening options in our RAW converters and image processors (PS, Lightroom, etc).

APS-C sensors take more sharpening. Since sharpening is not an unlimited good, it's possible to equalize the two at ISOs where noise is not emphasized by the greater degree of sharpening required for APS-C. This is true through about ISO 800.

For the same reasons small differences between lenses are simply not worth worrying about any more. In the film days lens sharpness and contrast were of paramount importance because you were typically stuck with the result. Now if two lenses are close, USM and local contrast enhancement can make up the difference.

Knowing how to optimize your images in post for a particular application/print size trumps many of the equipment differences people love to obsess about.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 22, 2013, 09:11:32 AM
Images talk much better than words when you are talking about photography. I decided to test it myself, and took my 60D, and 5D Mark II, and attached the same 35mm prime lens, and took the same shot. The 5D image of 5616 x 3744 I cropped to 1.6, which gave me 3510 x 2340. I then downsampled the 60D image to the same size, and took a 100% crop of both for screen.

So you threw away any detail resolved by the 60D but not by the cropped center of the 5D2. Why would you expect a different result then the one you got?

I'll be the first to say that with current bodies the crop reach advantage only comes into play if you're making large prints from files which are cropped even further than APS-C. It is there. I've got 9-10 MP, 16x20, 7D sports prints that would not have worked with the roughly 3 MP left over had I been shooting a 5D2. But if you're making 13x19's that aren't cropped any further, you'll never see a difference.

But that still doesn't excuse performing your test in a manner which purposely throws away any detail gain in the 60D file. Would you do that in real life? (Same question for the test which started this thread: would you produce prints with no sharpening? Or do you blindly apply equal sharpening to everything regardless of subject / lighting / lens / sensor / final application and view size?)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Rocky on January 22, 2013, 02:16:11 PM
The original post talks about "sharpness". A few posts are comparing DR, noise between the two formats. These are "picture quality", not sharpness only.  Some poster throw in "post production", that is not a valid arguement either. My take on this subject are:
1. For the same pixel count on both formats, both can be as sharp as each other,  assuming that the lens can out resolve both sensor in the imaging area. That will put a lot of stress on the lens for APS-C sensor. The lens need 1.6 time reolving power compare to the FF.
2. There are isolated incident that the APS-C can actually sharper than the FF if the lens use for FF have a severe problem in curvature of field or severe unsharp conrners. Since APS-C snesor only using the center part of the FOV of the lens. These problem may not exist. Therefore the APS-C is actually sharper.
3. FF will be sharper if the lens cannot out resolve the APS-C sensor but it will out resolve  the FF.
4. There is no doubt that FF will have better picture quality than thre APS-C, due to less noise, better DR.
5. The above piont is assuming that the lens is not being diffraction limited. The DOF is not affecting the sharpness either
6. In print, most of the difference will not be obvious due to the printing process.
7. How many people can tell the difference in music between  amplifier with 0.01% distotion and amplifier with 0.005 % distortion??
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 22, 2013, 04:37:06 PM
nr4
there are APS with the same DR as 24x36, example  D7000 and D800

And Pentax K5, K30, K-x - all Sony chip
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TheSuede on January 22, 2013, 07:30:23 PM
For one, I asked you what exactly you meant by "the APS-C lens has to be better than the FF lens"?

I followed that up with a clarifying question asking if you were talking about two different lenses such as one EF-S lens and one EF lens.

Sorry if I was the cause of any additional confusion... :)

-Yes, to get two images, one taken with APS and one taken with FF appear equally sharp when viewed at equal presentation size in your presentation format of choice, the lens used on the APS camera needs to be sharper, when sharpness is defined by "lines or line-pairs per mm".

-Yes, at least I am talking about two different lenses in the comparison. Why compare an 85mm on FF with an 85mm on APS? they don't "do" the same thing any more. If the shot taken with the FF camera was at a 10 feet target distance, you'd have to back of to 16 feet to get the same framing on APS. And by backing off to 16 feet, you change the perspective of the shot so much that it wouldn't even be the "same shot" any more.

Taking that into account is where the "FF is sharper than APS" starts to make sense....
Using a 135L 2.0 wide open on a 5D3 gives the same field of view, the same short DoF and the same amount of noise as using the 85L 1.2 on a 60D. But the 135 on 5D3 image will be a LOT sharper and more contrasty.

For the same reason, a bog-standard 85/1.8 on FF gives sharper images with the same short DoF as a 50L 1.2 does on APS. And a 50mm vs 35mm F1.4 on APS and so on.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Rocky on January 22, 2013, 08:55:38 PM
For one, I asked you what exactly you meant by "the APS-C lens has to be better than the FF lens"?

I followed that up with a clarifying question asking if you were talking about two different lenses such as one EF-S lens and one EF lens.

Sorry if I was the cause of any additional confusion... :)

-Yes, to get two images, one taken with APS and one taken with FF appear equally sharp when viewed at equal presentation size in your presentation format of choice, the lens used on the APS camera needs to be sharper, when sharpness is defined by "lines or line-pairs per mm".

-Yes, at least I am talking about two different lenses in the comparison. Why compare an 85mm on FF with an 85mm on APS? they don't "do" the same thing any more. If the shot taken with the FF camera was at a 10 feet target distance, you'd have to back of to 16 feet to get the same framing on APS. And by backing off to 16 feet, you change the perspective of the shot so much that it wouldn't even be the "same shot" any more.

Taking that into account is where the "FF is sharper than APS" starts to make sense....
Using a 135L 2.0 wide open on a 5D3 gives the same field of view, the same short DoF and the same amount of noise as using the 85L 1.2 on a 60D. But the 135 on 5D3 image will be a LOT sharper and more contrasty.

For the same reason, a bog-standard 85/1.8 on FF gives sharper images with the same short DoF as a 50L 1.2 does on APS. And a 50mm vs 35mm F1.4 on APS and so on.
Sharpness has got nothing to do with perspective, or DoF. You quoted all the lenses are wide open for the tests. It is not fair either. Every body knows that ALL lenses is not in their best behaviour when they are wide open ( more distortion, less resolution and less contrast ). Are you sure that the lenses can out resolve the APS-C sensor under test??? if not, then the result becomes a test of the lenses, not the sharpness of the sensor.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: p666 on January 23, 2013, 04:24:16 AM
Images talk much better than words when you are talking about photography. I decided to test it myself, and took my 60D, and 5D Mark II, and attached the same 35mm prime lens, and took the same shot. The 5D image of 5616 x 3744 I cropped to 1.6, which gave me 3510 x 2340. I then downsampled the 60D image to the same size, and took a 100% crop of both for screen.

So you threw away any detail resolved by the 60D but not by the cropped center of the 5D2. Why would you expect a different result then the one you got?

I'll be the first to say that with current bodies the crop reach advantage only comes into play if you're making large prints from files which are cropped even further than APS-C. It is there. I've got 9-10 MP, 16x20, 7D sports prints that would not have worked with the roughly 3 MP left over had I been shooting a 5D2. But if you're making 13x19's that aren't cropped any further, you'll never see a difference.

But that still doesn't excuse performing your test in a manner which purposely throws away any detail gain in the 60D file. Would you do that in real life? (Same question for the test which started this thread: would you produce prints with no sharpening? Or do you blindly apply equal sharpening to everything regardless of subject / lighting / lens / sensor / final application and view size?)

Ok you do have a point, however, taken the same files, and this time taken the same 3510x2340 crop on the 5D to get the same perspective as the original crop 60D. Now I upsampled the 5D image in Photoshop to the original APS-C size of 5184x3456. Then have taken a 1:1 pixel crop of the centre to compare. Unfortunately there is a slight brightness difference due to changes in ambient light. Quality appears to be very very similar again; there is no disadvantage to simply cropping a FF shot in this instance. Well for 60D vs 5DMk2, although yes, the Mk2 is 3x the price.

5D image:
http://farm9.staticflickr.com/8218/8407024129_52e33f3df5_o.jpg (http://farm9.staticflickr.com/8218/8407024129_52e33f3df5_o.jpg)

60D image:
http://farm9.staticflickr.com/8211/8407024335_b175c2d3c9_o.jpg (http://farm9.staticflickr.com/8211/8407024335_b175c2d3c9_o.jpg)

I'd be interested in seeing a 7D vs 5D Mk2 under the same scenario to see the differences if any. Taking the same lens, mounting them on the other body and isolating the same area as taken by the crop sensor.

2. There are isolated incident that the APS-C can actually sharper than the FF if the lens use for FF have a severe problem in curvature of field or severe unsharp conrners. Since APS-C snesor only using the center part of the FOV of the lens. These problem may not exist. Therefore the APS-C is actually sharper.

I don't see why, because if you were taking the same lens on the full frame, even if it had bad corners, if you took a center 1.6 crop size on the FF to get the same FOV, you would be throwing away the FF bad corners. It would be same as then comparing the same image area. Nearly every lens chart I have ever looked at the lens is sharper in the middle, so unless you were comparing edge of FF to centre of APS-C (which is not really a reasonable comparison) that is not the case.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 23, 2013, 05:40:58 AM
@p666, I posted some examples on page 2 of this thread done by my partner in Building Panoramics between 5D mk2 and 650D. I think this is more or less the same sensor as 7D.

However we didn't do it as you describe: it was non scientific, used different lenses to get same focal length. At ISO 100. I can assure you that in this scenario there was just no difference.
Apart from DoF.

Our conclusion with modern APS is that if you're shooting low ISOs, have good lenses and don't require ultra wides there is no difference. Also this thread has highlighted that many people really don't understand what is happening when you enlarge the digital info from you camera chip - either on screen or in print.

If you choose ( new ) full frame and want to keep same focal length and speed there are huge cost implications so the thread has had relevance. For many people their choice of FF will be because of personal and not necessarily technical reasons, and there would be zero differences in their pictures if they had been shot on good APS.

Me? I use FF because I want ultra wide, I want my lenses focal length to be what I understand from 35mm, and I can't stand expensive cameras with pop up flash.

@ dtaylor, really you had the last word in your post about post processing in digital. This is so true.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Rocky on January 23, 2013, 02:09:22 PM
2. There are isolated incident that the APS-C can actually sharper than the FF if the lens use for FF have a severe problem in curvature of field or severe unsharp conrners. Since APS-C snesor only using the center part of the FOV of the lens. These problem may not exist. Therefore the APS-C is actually sharper.

I don't see why, because if you were taking the same lens on the full frame, even if it had bad corners, if you took a center 1.6 crop size on the FF to get the same FOV, you would be throwing away the FF bad corners. It would be same as then comparing the same image area. Nearly every lens chart I have ever looked at the lens is sharper in the middle, so unless you were comparing edge of FF to centre of APS-C (which is not really a reasonable comparison) that is not the case.
If you read my post carefully, I started by staying that both FFand APS-C are of the same pixel count. Also sharpness has got nothing to do with FOV or DOF. Your disussion talks about cropping the FF to APS-C size. Therefore you have already thrown away more than half of the pixel from FF. Do you expect a 10 Mp picture to be sharper than a 22 MP APS-C picture with an very sharp lens (center area only)??
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 23, 2013, 02:22:02 PM
@ Rocky : + 1

If nothing else this thread has shown many people don't realise that digital enlargement is all down to the number of pixels on the sensor, and not the physical dimensions of the sensor "format", unlike film format.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Rocky on January 23, 2013, 02:41:21 PM
2. There are isolated incident that the APS-C can actually sharper than the FF if the lens use for FF have a severe problem in curvature of field or severe unsharp conrners. Since APS-C snesor only using the center part of the FOV of the lens. These problem may not exist. Therefore the APS-C is actually sharper.

well, you have soon  24x36 with the same pixel density then you have both cropping and 24x36 to chose between.
as todays d800 APS crop 15,3Mp. Next will be 54Mp 24x36 if they keep  the schedule and the APS crop 24Mp
[/quote}
My discussion is based on both FF and APS-C ARE of the same pixel count. Not pixel density.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 23, 2013, 03:56:16 PM
Sharpness has got nothing to do with perspective, or DoF.
I disagree. That's not even true when you only shoot ISO test charts. The larger DoF, the smaller the circle of confusion and the higher the resolution/sharpness (disregarding diffraction etc.).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 23, 2013, 03:59:34 PM
Some poster throw in "post production", that is not a valid arguement either.

The discussion is merely academic apart from post production. Nobody publishes images without post work, or at the very least non-neutral camera settings.

Quote
1. For the same pixel count on both formats, both can be as sharp as each other,  assuming that the lens can out resolve both sensor in the imaging area. That will put a lot of stress on the lens for APS-C sensor. The lens need 1.6 time reolving power compare to the FF.

This is false. Resolution is not a single number. It's a graphed MTF curve of contrast achieved at ascending resolutions as recorded on the sensor/film. The higher the resolution, the lower the detail contrast or sharpness.

If you have a FF and APS-C sensor with equal pixel counts, and all other factors are equal (lens, scene, etc), then the APS-C sensor will produce an image that is less sharp than the FF sensor. Within its cropped area, it's recording at a higher resolution than the FF sensor, and the lens will deliver less contrast at that higher resolution.

Quote
2. There are isolated incident that the APS-C can actually sharper than the FF if the lens use for FF have a severe problem in curvature of field or severe unsharp conrners. Since APS-C snesor only using the center part of the FOV of the lens. These problem may not exist. Therefore the APS-C is actually sharper.

Yes, there are some lenses where this is the case.

Quote
3. FF will be sharper if the lens cannot out resolve the APS-C sensor but it will out resolve  the FF.

Sort of. Again, resolution is not a hard number. It would be more accurate to say that FF will be sharper than expected (see point 1) if the lens MTF curve favors lower resolutions, i.e. if it really drops towards the bottom of the chart in the region where the APS-C sensor sits.

It should also be noted that contrary to popular belief the vast majority of lenses can out resolve current DSLR pixel pitches at MTF10. You would almost need a coke bottle to fail to do so. If you want to see lens challenging pixel pitches you have to look at compact cameras.

Quote
4. There is no doubt that FF will have better picture quality than thre APS-C, due to less noise, better DR.

Way too broad of a statement. There are actually people who will take this to mean that a 1Ds (original) will have better IQ then a 60D or 7D. It won't. Technology is at least as important as sensor surface area (noise) and pixel size (DR). Further, at this stage of technology, there are ISOs where noise is simply a non issue between the two formats.

Quote
6. In print, most of the difference will not be obvious due to the printing process.

I would say it's more due to scaling, but agreed.

Quote
7. How many people can tell the difference in music between  amplifier with 0.01% distotion and amplifier with 0.005 % distortion??

In a double blind study I would be surprised if anyone could.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 23, 2013, 04:26:21 PM
@ Rocky : + 1

If nothing else this thread has shown many people don't realise that digital enlargement is all down to the number of pixels on the sensor, and not the physical dimensions of the sensor "format", unlike film format.
Yes, digital enlargement only takes into account the number of MP. But that argument is conveniently missing out many significant parts of the overall image capture process.

Light, and the scene captured by the lens/camera are analogue. The resulting print (unless its a particularly low res digital print) does its best to look analogue. And similarly speaking, with a good enough display (such as a retina display), its again a good approximation of analogue - and both print and display have light coming off them (reflected or lit) which is analogue, which is how your eyes can see it. With a digital camera, the in between bits of the process are a combination of analogue and digital. It starts off with a lens which is very much analogue. That creates an analogue imaging circle. That in turn is captured by an analogue sensor, which generates analogue electrical signals, fed through analogue amplifiers, before finally getting converted to digital. Only after all that is the RAW file or JPG created and stored. Then its transferred to a computer, possibly had PP done on it, before finally leaving the digital domain when it gets put into some sort of approximation of analogue so we can see it.

By talking about one stage of that process from half way through (the captured MP), and then talking about how magnifying that is the only thing which matters is missing out half the picture.

Comparing two similar sized sensors results in quite similar results, so comparing APS-C to FF is not so clear cut to visualise which is best. So to prove a point, lets compare a much smaller 18MP sensor such as the Panasonic ZS30 to a full frame 18MP sensor such as the 1D X. Printing both images at the same size has exactly the same digital enlargement, but the tiny sensored Panasonic compact analogue image will have been enlarged much more. And I can't imagine anyone trying to pretend that a 1D X, even with the same effective focal length, aperture and ISO will produce images when printed large that could be mistaken for ones taken with the Panasonic. The only way the two could ever look comparable is if their pictures are printed almost postage stamp small - that way the Panasonic analogue image has been enlarged by a more sensible amount, hiding its faults much better.

If we are talking about a purely digital image with no noise, diffraction, lens softness etc. such as CGI, then yes, MP is king. After all, enlarging can only be an enlargement of each pixel, and we don't want to enlarge it to the point where it looks pixelated. But digital photos are not perfect digital files. They are merely digital representation of an analogue capture of the scene. Enlargement of the sensor is the key factor to quality, not enlargement of each subdivision of one stage of the process.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 23, 2013, 04:57:03 PM
Full frame is not sharper than APS-C. It has shallower depth of field when framed the same, requiring a higher f-stop to get more in focus. Why did Ansel belong to the f64 club? Because much less than f64, even with tilts, and not much is in focus. Full Frame has the grim problem of using the bad part of lenses too, making corners truly grim on all but the most fine of lenses.

But, mainly, a pixel is a pixel, and it really doesn't matter what size the sensor was. Full Frame can deliver a better image sometimes, but there is a reason Canon's lead Action camera was a crop body (APS-H). Most likely, tachnology has progressed to the point where the 7D MK II will have better IQ at 1.6 crop than the old 1d MK IV had at its 1.3 crop.

APS-C has some serious advantages. Google "7D bird photography". You will see some amazing things...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Rocky on January 23, 2013, 05:07:35 PM
Sharpness has got nothing to do with perspective, or DoF.
I disagree. That's not even true when you only shoot ISO test charts. The larger DoF, the smaller the circle of confusion and the higher the resolution/sharpness (disregarding diffraction etc.).
As long as your lens can out resolve the senser, the DOF does not matter any more. Also the DOF is governed by the acceptable size of circle of confussion.  As long as you have the acceptable size of circle of conffussion, your DOF can either be  1 inch or 10 ft, both will give you the same result on the point of focus.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 23, 2013, 05:23:04 PM
Talking of "action cameras" I was really surprised to see how many 7Ds were being used at the London Olympics.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 23, 2013, 05:38:41 PM
Full frame is not sharper than APS-C. It has shallower depth of field when framed the same, requiring a higher f-stop to get more in focus. Why did Ansel belong to the f64 club? Because much less than f64, even with tilts, and not much is in focus. Full Frame has the grim problem of using the bad part of lenses too, making corners truly grim on all but the most fine of lenses.

But, mainly, a pixel is a pixel, and it really doesn't matter what size the sensor was. Full Frame can deliver a better image sometimes, but there is a reason Canon's lead Action camera was a crop body (APS-H). Most likely, tachnology has progressed to the point where the 7D MK II will have better IQ at 1.6 crop than the old 1d MK IV had at its 1.3 crop.

APS-C has some serious advantages. Google "7D bird photography". You will see some amazing things...
The reason the Canon 1D line of cameras had a 1.3x crop is when it was introduced in 2001, it was the largest sensor Canon could source - as far as I know, it was the largest in a production camera at the time. FF sensors didn't hit the market until the Contax N Digital was introduced in 2002. That same year, Canon introduced the much more successful FF 1Ds. Due to the limits of the technology it had much slower read out, so it was nowhere near as fast as the 1.3x crop sensor 1D. They continued as two lines of bodies - FF for the highest image quality, 1.3x crop for speed. Nikon managed to combine FF and speed with the D3 (although it was slightly slower than 1D mk III and much lower res than 1Ds mk III). The D4 was their successor, and Canon's rather elaborate answer to it was to combine the two 1 series lines with the 1D X.

Granted, sometime lots in focus is desired. But that's why lenses can be stopped down, and why tilt and shift lenses exist. To get as large a depth of field on FF as on 1.6x, simply use an aperture 1.6x smaller. You will need an ISO just over a stop higher if you want the same shutter speed, but the advantage of FF is still there. And TS-E lenses take things to another level. When you don't want a huge DoF, try a lens like the 70-200 II or the 100L. What's in focus is capable of being so detailed even at the edges of the frame that you'll no doubt be immediately aware of the difference FF makes.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 23, 2013, 06:29:49 PM
I see there's still a great deal of misinformation going on in this thread.

The simple version is that, even if the number of megapickles is exactly the same, the larger format will intrinsically produce sharper images.

I'm attaching an image to demonstrate this. It's a simple enough experiment that anybody can perform: set up a still life. Take two images, one with a long lens and the other with a wide lens -- or with a zoom at either end of its range. Crop the wide image to the same field of view as the telephoto image, and scale the two to the same pixel dimensions. You're left with two images with the exact same number of megapickles, and everything else is either constant or can be controlled for. The sensors of the two images is identical, so you've got the same S/N ratio, the same everything.

To do the most fair comparison possible, you'll want to use the same shutter speed for both images, an aperture sufficiently smaller for the telephoto to match the depth of field, and an equivalent higher ISO to keep the exposure the same. That's exactly what I did below.

And, you can clearly see: the image generated with the larger, 135 format sensor is significantly sharper than the image generated with the smaller, P&S-sized sensor. And, again, I stacked the deck against the larger format in every reasonable way I could.

Pixel density is important, yes. But so is format size. For the absolute best results, you'll want the highest pixel density you can get in the largest format you can get. But, if you have a choice between two cameras of different formats and different megapickles, go with the bigger format. (With, of course, the usual caveats that sufficient technology age can skew the results.)

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 23, 2013, 07:49:05 PM
The simple version is that, even if the number of megapickles is exactly the same, the larger format will intrinsically produce sharper images.

All other things being equal, and assuming glass that does not have serious problems at the edges which are trimmed by APS-C...yes.

Quote
It's a simple enough experiment that anybody can perform: set up a still life. Take two images, one with a long lens and the other with a wide lens -- or with a zoom at either end of its range. Crop the wide image to the same field of view as the telephoto image, and scale the two to the same pixel dimensions.

While I agree with the principle, this test does not demonstrate it. The differences are way too large to be reliable (different lenses; scaling algorithms).

Quote
And, you can clearly see: the image generated with the larger, 135 format sensor is significantly sharper than the image generated with the smaller, P&S-sized sensor. And, again, I stacked the deck against the larger format in every reasonable way I could.

Nah, the differences cut against the WA shot. Again, I agree in principle, but this test isn't the way you demonstrate it.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 23, 2013, 07:58:51 PM
Nah, the differences cut against the WA shot.

Seriously?

The wide-angle shot is with the sharpest wide-angle lens ever made for the format, and one of the sharpest lenses ever made, period. And it's at its sweet spot for aperture. Plus, the shot was at ISO 100.

The telephoto shot was with a lens with a built-in soft focus filter (with the filter turned to its least soft setting, of course),  fer chrissakes, and it was shot at f/32 (waaaaay past the point of diffraction), and it was shot at ISO 6,400.

I mean, seriously. I compared a Coke bottle with the Hubble, and the Coke bottle still beat the Hubble.

If you don't think that this test demonstrated the importance of format size over pixel dimensions...well...all sorts of unflattering adjectives come to mind, with "hopeless" being the one best suited for a family-friendly forum.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: skitron on January 23, 2013, 08:18:14 PM
7. How many people can tell the difference in music between  amplifier with 0.01% distotion and amplifier with 0.005 % distortion??

In a double blind study I would be surprised if anyone could.

Not that it amounts to a hill of beans for this discussion, but it's actually pretty easy if you listen to the cymbals and the speakers/headphones are up to the task.

[/tangent off]  ;)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 24, 2013, 01:51:30 AM
Nah, the differences cut against the WA shot.

Seriously?

The wide-angle shot is with the sharpest wide-angle lens ever made for the format, and one of the sharpest lenses ever made, period. And it's at its sweet spot for aperture. Plus, the shot was at ISO 100.

The telephoto shot was with a lens with a built-in soft focus filter (with the filter turned to its least soft setting, of course),  fer chrissakes, and it was shot at f/32 (waaaaay past the point of diffraction), and it was shot at ISO 6,400.

I mean, seriously. I compared a Coke bottle with the Hubble, and the Coke bottle still beat the Hubble.

If you don't think that this test demonstrated the importance of format size over pixel dimensions...well...all sorts of unflattering adjectives come to mind, with "hopeless" being the one best suited for a family-friendly forum.

Cheers,

b&
You're completely right. With those lenses and those settings, that test couldn't have been more stacked against the full frame setup. Yet full frame easily and conclusively won.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 24, 2013, 03:10:34 AM
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.  Yes, I do know that you downsized the image from the telephoto, but it makes for the same thing in a conparison.

Basically, you have shown the image of the bird that covers the whole sensor - that is makes use of most of the megapixels - is far better than have it cover just a few pixels at the centre of the sensor.  That is not a relevant comparison for FF vs crop.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 24, 2013, 03:22:24 AM
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.  Yes, I do know that you downsized the image from the telephoto, but it makes for the same thing in a conparison.

Basically, you have shown the image of the bird that covers the whole sensor - that is makes use of most of the megapixels - is far better than have it cover just a few pixels at the centre of the sensor.  That is not a relevant comparison for FF vs crop.
OK - here's a simple question. Has anyone got a Pentax Q (12MP, small sensor) and a 5Dc (12MP, FF sensor) - if we look at a comparison of the two, it should solve this issue once and for all, even though the 5Dc is using much older tech.

The point of TrumpetPower's test is both of them are adjusted to a very low number of MP, therefore they're both on an equal footing (downsampling a high MP image to low MP is very similar to starting with low MP in the first place).

Comparing two similar sized sensors (FF and 1.6x) is bound to not return very dramatic difference in quality. We are just picking at the fine details here as they're both great in the big scale of things. That is why the tests should happen with a larger difference in sensor size if we want to conclusively solve this. That's why something along the lines of a Pentax Q and 5Dc comparison will solve the issue once and for all.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 24, 2013, 04:50:30 AM
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.  Yes, I do know that you downsized the image from the telephoto, but it makes for the same thing in a conparison.

Basically, you have shown the image of the bird that covers the whole sensor - that is makes use of most of the megapixels - is far better than have it cover just a few pixels at the centre of the sensor.  That is not a relevant comparison for FF vs crop.

+1

There have been some really confused posts  ::)

IF lenses were perfect ( which they are not ), and IF pixels of any size were perfect ( which they are not), and IF the laws of physics didn't apply ( which they do ) then there would be no difference in the resulting enlargement of the information from equal pixel sensors of any format.

I don't think there is anyone on this thread who believes that lenses and pixels are perfect.

And by the way how many times have we seen people comparing APS to FF using a zoom such as the 24-105 to get same field of view on both cameras, and all they do is end up showing the different resolution characteristics of that lens at the different focal lengths   ;D
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: verysimplejason on January 24, 2013, 05:04:09 AM

But, mainly, a pixel is a pixel, and it really doesn't matter what size the sensor was. Full Frame can deliver a better image sometimes, but there is a reason Canon's lead Action camera was a crop body (APS-H).

Where were you when 1DX was born?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: iP337 on January 24, 2013, 06:30:27 AM
For one, I asked you what exactly you meant by "the APS-C lens has to be better than the FF lens"?

I followed that up with a clarifying question asking if you were talking about two different lenses such as one EF-S lens and one EF lens.

Sorry if I was the cause of any additional confusion... :)

-Yes, to get two images, one taken with APS and one taken with FF appear equally sharp when viewed at equal presentation size in your presentation format of choice, the lens used on the APS camera needs to be sharper, when sharpness is defined by "lines or line-pairs per mm".


Right, sensor sizes, output resolutions and print sizes aside; any sensor with a higher pixel density (smaller pixels) with resolve finer details, commonly measured in Line-Pairs per mm (or how many lines you can squeeze into a millimeter). 

So an equal pixel APS-C sensor has the potential of resolving finer details but the lens needs to be sharper, many of todays lenses, even EF-s lenses, are made for 135 (Full Frame 35mm) sharpness but APS-C needs sharper than that because it's trying to resolve finer details.  So blowing up to 100% (pixel level) on the APS-C image will look softer than a 100% 135 image because by going to "pixel level" you are actually magnifying the APS-C image about 50% larger than the 135 image.

This is also one of the reasons why the GH2 with a 4/3 sensor can resolve near 1000 lines in 1080p video vs the 5D2 resolving about 700 lines in 1080p and the older 2/3 HD camcorders did 1000 lines easy.  Now of course there is still diffraction to worry about, 5D2 starts to limit around f/11 while the 7D starts at f/6.3, go too small (pixel size that is) and you'll start out limited wide open!  APS-C has a deeper DoF so it about evens out; but this is why I think the high megapixel full frames like the D800 isn't a practical camera, you get a low f-stop diffraction limit with a shallow DoF, which is only really usable at f/4-f/5.6. 

The best setup to test this is with a 135 and an APS-C with the same output resolution (D3x and NEX7 maybe), get the sharpest glass you can find (a Leica Summicron or maybe that Ziess 35/2.8) shoot and compare.

But no matter what you find it doesn't change the fact that some things are better with 135 and some better with APS-C.  If you need shallow DoF, higher dynamic range or low light shots than APS-C will not work but if you need the extra reach but can't afford an exotic telephoto, need finer details and have the lenes that can resolve them or need a deeper DoF without sacrificing light than grab your APS-C.  There is a reason why the 1Dx, 1Dc and Nikon Full Frame DSLRs have an APS-C mode...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: rs on January 24, 2013, 07:34:33 AM
Right, sensor sizes, output resolutions and print sizes aside; any sensor with a higher pixel density (smaller pixels) with resolve finer details, commonly measured in Line-Pairs per mm (or how many lines you can squeeze into a millimeter). 

So an equal pixel APS-C sensor has the potential of resolving finer details but the lens needs to be sharper, many of todays lenses, even EF-s lenses, are made for 135 (Full Frame 35mm) sharpness but APS-C needs sharper than that because it's trying to resolve finer details.  So blowing up to 100% (pixel level) on the APS-C image will look softer than a 100% 135 image because by going to "pixel level" you are actually magnifying the APS-C image about 50% larger than the 135 image.

This is also one of the reasons why the GH2 with a 4/3 sensor can resolve near 1000 lines in 1080p video vs the 5D2 resolving about 700 lines in 1080p and the older 2/3 HD camcorders did 1000 lines easy.  Now of course there is still diffraction to worry about, 5D2 starts to limit around f/11 while the 7D starts at f/6.3, go too small (pixel size that is) and you'll start out limited wide open!  APS-C has a deeper DoF so it about evens out; but this is why I think the high megapixel full frames like the D800 isn't a practical camera, you get a low f-stop diffraction limit with a shallow DoF, which is only really usable at f/4-f/5.6. 

The best setup to test this is with a 135 and an APS-C with the same output resolution (D3x and NEX7 maybe), get the sharpest glass you can find (a Leica Summicron or maybe that Ziess 35/2.8) shoot and compare.

But no matter what you find it doesn't change the fact that some things are better with 135 and some better with APS-C.  If you need shallow DoF, higher dynamic range or low light shots than APS-C will not work but if you need the extra reach but can't afford an exotic telephoto, need finer details and have the lenes that can resolve them or need a deeper DoF without sacrificing light than grab your APS-C.  There is a reason why the 1Dx, 1Dc and Nikon Full Frame DSLRs have an APS-C mode...
All makes sense, except the smaller pixels of an equal MP crop sensor means each pixel is detecting less light. As a result, there is a weaker electrical signal which requires more amplification to reach the same industry standard ISO settings. Which is why the older the tech/the higher the pixel density, the more NR (software or even built into the sensor) is applied to further soften the image.

Also, Canon don't offer an APS-C mode on any of their FF cameras. Nikon offer it on all of theirs, but that's only because their APS-C lenses can be physically mounted on FF cameras, the rear element clears the FF mirrors, and they took the decision to allow people to shoot with such lenses without having to crop later.

Crop sensors initially existed due to cost constraints - in the early days of DSLR's, FF was just a pipe dream. In 2002 it became a reality, but a very expensive one. It was only in 2007 that Nikon eventually offered FF, and now we have budget FF offerings from both Canon and Nikon, and FF SLT's and compacts from Sony. FF sensors are becoming more cost effective, their advantages are real, but their is a trade off - lenses - their size, weight and price. However we've already got that disadvantage compared to compact cameras anyway.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:04:02 AM
Right, sensor sizes, output resolutions and print sizes aside

Squeeze me?

What, exactly, do you think people are using cameras for if not to output images and make prints?

It's incredible.

I post clear, indisputable, incontrovertible evidence that a full-frame camera with a decidedly "meh" lens with a pinhole aperture at high ISO absolutely blows away a P&S camera with a state-of-the-art lens at ideal aperture and base ISO...and all people can do is go on and on about how there's a theoretical possibility that a smaller camera maybe possibly could perform equally to a larger one if the DeLorean hits the wire at exactly 88 mph at the stroke of midnight when the moon is ascending Uranus.

All this strum und drang about sensors that violate the laws of physics and lenses that require materials and manufacturing processes that don't exist, just to argue that somebody could theoretically make a small-sensor camera almost as good as a large-sensor camera if only there were flying unicorn ponies to deliver them down chimneys at Thanksgiving.

I'm sorry, people, but this is just nuts. Common wisdom says that bigger is better. Commercial photographers say that bigger is better. Clients say that bigger is better. Editors say that bigger is better. Critics say that bigger is better. Customers say that bigger is better. Manufacturers say that bigger is better. The back of the envelope says that bigger is better. Basic geometry says that bigger is better. Empirical testing says that bigger is better.

So where on Earth does all this religious passion come from that smaller can be just as good as big, if you just stack the deck in its favor sufficiently?

Look, the smaller formats not only have their place, they're actually wonderful. They still produce superlative results, more than enough, outperform the 80/20 rule, and they do so while being lighter and cheaper and easier to fit in your pocket. What's not to love?

But they do not, and never will, beat the larger formats in any measure of image quality.

But so what? That's not their purpose. That's not why you buy them. That's not what you use them for.

When sheer image quality is the primary concern, go with the larger format. When there are other considerations in addition to image quality, such as handling or price, the smaller formats will likely win out.

No P&S is ever going to have anywhere near the image quality of an 8x10 view camera -- but nobody's ever going to stash an 8x10 view camera in a purse and snap a picture of a friend in a nightclub, either!

Horses for courses, guys. Horses for courses.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 24, 2013, 09:18:49 AM
Full frame is not sharper than APS-C. It has shallower depth of field when framed the same, requiring a higher f-stop to get more in focus. Why did Ansel belong to the f64 club? Because much less than f64, even with tilts, and not much is in focus. Full Frame has the grim problem of using the bad part of lenses too, making corners truly grim on all but the most fine of lenses.

But, mainly, a pixel is a pixel, and it really doesn't matter what size the sensor was. Full Frame can deliver a better image sometimes, but there is a reason Canon's lead Action camera was a crop body (APS-H). Most likely, tachnology has progressed to the point where the 7D MK II will have better IQ at 1.6 crop than the old 1d MK IV had at its 1.3 crop.

APS-C has some serious advantages. Google "7D bird photography". You will see some amazing things...
The reason the Canon 1D line of cameras had a 1.3x crop is when it was introduced in 2001, it was the largest sensor Canon could source - as far as I know, it was the largest in a production camera at the time. FF sensors didn't hit the market until the Contax N Digital was introduced in 2002. That same year, Canon introduced the much more successful FF 1Ds. Due to the limits of the technology it had much slower read out, so it was nowhere near as fast as the 1.3x crop sensor 1D. They continued as two lines of bodies - FF for the highest image quality, 1.3x crop for speed. Nikon managed to combine FF and speed with the D3 (although it was slightly slower than 1D mk III and much lower res than 1Ds mk III). The D4 was their successor, and Canon's rather elaborate answer to it was to combine the two 1 series lines with the 1D X.

Granted, sometime lots in focus is desired. But that's why lenses can be stopped down, and why tilt and shift lenses exist. To get as large a depth of field on FF as on 1.6x, simply use an aperture 1.6x smaller. You will need an ISO just over a stop higher if you want the same shutter speed, but the advantage of FF is still there. And TS-E lenses take things to another level. When you don't want a huge DoF, try a lens like the 70-200 II or the 100L. What's in focus is capable of being so detailed even at the edges of the frame that you'll no doubt be immediately aware of the difference FF makes.

I have shot full frame. I even have a full frame camera. Actually, I have three full frame camera, if you count my Spotmatic and Kiowa. I even have two large format cameras, Crown Graphics.... What I am saying is that full frame is not the all end all. There are times and places and needs for smaller sensors, which will in their case well out perform a larger sensor.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 24, 2013, 12:36:06 PM
Right, sensor sizes, output resolutions and print sizes aside

I post clear, indisputable, incontrovertible evidence that a full-frame camera with a decidedly "meh" lens with a pinhole aperture at high ISO absolutely blows away a P&S camera with a state-of-the-art lens at ideal aperture and base ISO...

Your evidence was disputed by me and you did not bother to answer. Until you answer satisfactorily, your "proof" is not a proof and is certainly not indisputable. I am happy for my arguments to be disproved in a logical manner but will not take you seriously if you fail to consider them.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 01:05:55 PM
Right, sensor sizes, output resolutions and print sizes aside

I post clear, indisputable, incontrovertible evidence that a full-frame camera with a decidedly "meh" lens with a pinhole aperture at high ISO absolutely blows away a P&S camera with a state-of-the-art lens at ideal aperture and base ISO...

Your evidence was disputed by me and you did not bother to answer. Until you answer satisfactorily, your "proof" is not a proof and is certainly not indisputable. I am happy for my arguments to be disproved in a logical manner but will not take you seriously if you fail to consider them.

Alan, I was being gracious in ignoring your complaint, as it indicates that you really don't understand even the simplest fact about what a crop sensor camera actually is. Specifically:

Quote
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.

That is exactly what all crop format cameras do -- except, of course, that they don't have all the rest of the sensor to crop from, just the teeny weeny central section.

The Wikipedia article is not bad:

http://en.wikipedia.org/wiki/Image_sensor_format (http://en.wikipedia.org/wiki/Image_sensor_format)

But have a look at any P&S camera. Look at the focal length of the lens. Not the "35mm equivalent focal length," but the actual focal length, usually printed on the lens and always included in the specs. They're all ludicrously wide, if the were full-frame cameras. Something like a 4mm - 24mm zoom is not unusual; it would work out to a 24-135 "equivalent." So, if you were to take such a P&S camera and zoom all the way in to its most telephoto setting of "135mm equivalent," you would, indeed, be using a wide-angle lens and be blowing up a teeny weeny sensor, exactly what I did in that experiment.

And, yes, those P&S cameras take better pictures than just cropping away all but the teeny weeny central section of a full-frame camera, but only because they have sensors with insane pixel densities. Build a full-frame camera with the same pixel density and you'll wind up with a 150, 200 megapickle monster...and then, yes, cropping away all but the teeny weeny central section of a wide-angle image shot with that monster full-frame camera would result in the exact same picture as taken with the P&S camera.

Think back to the early days of digital photography, when even small cameras didn't have a single megapickle in their sensors. (Kodak was the first to reach the megapickle mark in '86.) Imagine you had a camera with a 4mm x 6mm sensor and a whopping 0.7 megapickles of resolution. Slap a 24mm lens on it, and you'd get the exact image on the right in my experiment -- pixel for pixel. That's the actual raw dump of the image, no post-processing, nothing. And that's as good as that camera can do.

Now, use the exact same tech to build a full-frame sensor...and you've got the 5DIII. Now, take another step, and imagine a full-frame sensor built using the same tech in today's megapickle P&S cameras.

That's the whole point of this illustration: that sensor size really does matter.

Is it the whole story? Of course not. I've already pointed out that, though an 8x10 view camera will mop the floor with a full-frame camera, you can't exactly go clubbing with it. But it is the whole story when it comes to image quality: all else being equal, bigger is always better.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 01:18:01 PM
bigger is always better if you talk about the same sensor tech

<sigh />

Have I even once indicated otherwise? I don't know how many times I've typed, "all else being equal" in this thread -- I can't count that high.

And your chart just proves that smaller is cheaper, nothing more. We already know that. Spend the money, and you'll get a full-frame sensor with the electronics of the P&S. Hell, the NSA probably has medium- or even large-format sensors with the electronics of a P&S, plus insanely long lenses better than anything you can buy from Canon, plus they're in orbit.

So what?

The question was whether or not sensor size matters. It does.

It really does boggle my mind that anybody would even think to dispute that, let alone argue for all the ways in which some other variable can compensate.

You know what else could make a small sensor outperform a bigger one than using newer and more expensive technology in the small sensor and older and cheaper technology in the big one?

Here's a short list.

You could put one of the world's greatest lenses in front of the small sensor but put a dirty, chipped Coke bottle in front of the big one. (Hey, that's not far off from what I did, and still the big sensor won!)

You could smear vaseline all over the big sensor but not over the small one.

Or, lastly, you could put the small sensor in a camera in the hands of a real photographer and put the big sensor in the hands of an Internet measurebator troll.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 24, 2013, 01:20:06 PM
Full frame is not sharper than APS-C. It has shallower depth of field when framed the same, requiring a higher f-stop to get more in focus. Why did Ansel belong to the f64 club? Because much less than f64, even with tilts, and not much is in focus. Full Frame has the grim problem of using the bad part of lenses too, making corners truly grim on all but the most fine of lenses.

But, mainly, a pixel is a pixel, and it really doesn't matter what size the sensor was. Full Frame can deliver a better image sometimes, but there is a reason Canon's lead Action camera was a crop body (APS-H). Most likely, tachnology has progressed to the point where the 7D MK II will have better IQ at 1.6 crop than the old 1d MK IV had at its 1.3 crop.

APS-C has some serious advantages. Google "7D bird photography". You will see some amazing things...
The reason the Canon 1D line of cameras had a 1.3x crop is when it was introduced in 2001, it was the largest sensor Canon could source - as far as I know, it was the largest in a production camera at the time. FF sensors didn't hit the market until the Contax N Digital was introduced in 2002. That same year, Canon introduced the much more successful FF 1Ds. Due to the limits of the technology it had much slower read out, so it was nowhere near as fast as the 1.3x crop sensor 1D. They continued as two lines of bodies - FF for the highest image quality, 1.3x crop for speed. Nikon managed to combine FF and speed with the D3 (although it was slightly slower than 1D mk III and much lower res than 1Ds mk III). The D4 was their successor, and Canon's rather elaborate answer to it was to combine the two 1 series lines with the 1D X.

Granted, sometime lots in focus is desired. But that's why lenses can be stopped down, and why tilt and shift lenses exist. To get as large a depth of field on FF as on 1.6x, simply use an aperture 1.6x smaller. You will need an ISO just over a stop higher if you want the same shutter speed, but the advantage of FF is still there. And TS-E lenses take things to another level. When you don't want a huge DoF, try a lens like the 70-200 II or the 100L. What's in focus is capable of being so detailed even at the edges of the frame that you'll no doubt be immediately aware of the difference FF makes.

I have shot full frame. I even have a full frame camera. Actually, I have three full frame camera, if you count my Spotmatic and Kiowa. I even have two large format cameras, Crown Graphics.... What I am saying is that full frame is not the all end all. There are times and places and needs for smaller sensors, which will in their case well out perform a larger sensor.

Can you please give us an example of when a smaller sensor would OUTPERFORM a larger sensor?  And I just mean the sensor.  Thanks.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 01:26:06 PM
YOU wrote
Build a full-frame camera with the same pixel density and you'll wind up with a 150, 200 megapickle monster...and then, yes, cropping away all but the teeny weeny central section of a wide-angle image shot with that monster full-frame camera would result in the exact same picture as taken with the P&S camera.

and I say NO

Well, thanks for so clearly demonstrating to all that you fail at introductory-level geometry (which is all this is really about).

Sorry. First your misinformation on ISO in that other thread, and now your misinformation on sensors. If you really are a professional photographer, if I were you I'd be deleting all these posts lest your clients discover your technical incompetence.

Even if it's all a giant misunderstanding due to a language barrier, it still demonstrates an inability on your part to understand the limits of your communication skills -- and communication is key with clients.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 24, 2013, 01:26:52 PM
The Great Picture > LF > MF > 35mm > APS-C > M4/3 > Compact Sensors

This shows that if your film is big enough, a Hanger door could be a lens.  8)
http://en.wikipedia.org/wiki/The_Great_Picture (http://en.wikipedia.org/wiki/The_Great_Picture)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 24, 2013, 01:53:38 PM
Nikon 5200 blow 5d of the road, if you have enough good lens on the Nikon

Technically true in terms of sensor performance.  Of course, comparing a camera from last year to a camera from 8 years ago isn't exactly an apples-to-apples comparison. 
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 24, 2013, 01:56:50 PM

Quote
Quote
Alan, I was being gracious in ignoring your complaint, as it indicates that you really don't understand even the simplest fact about what a crop sensor camera actually is. Specifically:
Quote
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.
Gracious is not a word that most people would apply to your style. And belittling your questioners does not refute arguments. It is perfectly obvious that a large format with a long focal length lens beats out a small format with the same number of megapixels with a short focal length lens, all things being equal, if they have the same field of view. But your "experiment" did not do that. Your set up had the long focal length lens with a narrow field of view and compared it with a short focal length with a wide field of view and then lost resolution from the small format by cropping.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 02:10:41 PM
It is perfectly obvious that a large format with a long focal length lens beats out a small format with the same number of megapixels with a short focal length lens, all things being equal, if they have the same field of view. But your "experiment" did not do that. Your set up had the long focal length lens with a narrow field of view and compared it with a short focal length with a wide field of view and then lost resolution from the small format by cropping.

Alan, are you serious?

Scenario a: two cameras, one with a 4.27mm x 6.4mm sensor and a 24mm lens, the other with a 24mm x 36mm sensor and a 135mm lens. Both sensors have 6.25µ pixels.

Scenario b: one camera with a 24mm x 36mm sensor with 6.25µ pixels. One image is made with a 24mm lens and cropped to only use the 4.27mm x 6.4mm central portion of the sensor; the other image is made with a 135mm lens and the full sensor.

Educate us: what, exactly, is the difference between those two scenarios?

Or are you somehow under the misimpression that lens focal length is a function of format size? Is that it? Do you think that a 24mm lens on a 4.27mm x 6.4mm sensor is still a wide-angle lens? If so, you need to brush up on your introductory optics. That small sensor would need a 4.27mm lens to produce the same field of view as a 24mm lens does on a 24mm x 36mm "full frame" sensor. That's why a 50mm lens is still a 50mm lens whether it's on a Rebel or a 5D, but it's a normal lens on the 5D and a telephoto on the Rebel. The lens hasn't changed, and it's still the exact same focal length as always, regardless of what camera you attach it to.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 24, 2013, 02:30:57 PM
I'm getting really confused on this thread.

With regard to Mikael's post on 5D and D5200, I thought the value of read noise was derived from the amount of photons that have not been converted to electrical charge. As 5Dc has whopping great pixels compared with D5200 when are able to receive far more photons and so the amount of non converted with be much higher number, and so the read noise will be much higher even if the efficiency of light conversion in the 5Dc and D5200 was the same.

So you'd expect 5D to have much higher read noise, or is my understanding of how read noise values are reached wrong ?


Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 02:40:46 PM
Nikon 5200 blow 5d of the road, if you have enough good lens on the Nikon

Technically true in terms of sensor performance.  Of course, comparing a camera from last year to a camera from 8 years ago isn't exactly an apples-to-apples comparison.

So, he's comparing Nikon's just-released high megapickle APC camera not to the 5DIII, but to the classic 5D?

Whoopee.

Maybe he can follow it up by racing a 2013 Accord against a Ferrari 125 S....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 03:29:57 PM
Nah, the differences cut against the WA shot.

Seriously?

There is no way to quantify and compensate for the many variables which are different. Your test, however much you think it proves the point, is simply invalid.

As for your argument about the lenses, it's pointless because the crop-n-scale trumps everything else. Even the f-stop selection in this case. You didn't have any where near as many pixels on target, and then you let a computer algorithm (which one? what settings?) fill in the missing data. This bears no analogy or relevance to having an actual APS-C sensor, of the same MP resolution, take the shot with the same lens and aperture positioned for the same FoV. (Side note: the soft filter argument was silly. That does not come into play on that lens unless you select it.)

Again, I agree in principle because the principles are well established and understood. But the test you posted was horribly flawed.

Quote
If you don't think that this test demonstrated the importance of format size over pixel dimensions...well...all sorts of unflattering adjectives come to mind, with "hopeless" being the one best suited for a family-friendly forum.

Nobody can tell what your test demonstrated because of all the confounding variables.

I've compared FF and APS-C a number of times...all other factors being equal...and I've always found the same thing: FF is sharper out of camera, but the range is small enough to be closed by bumping up sharpening in camera or post. When the sensors are otherwise comparable of course.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 03:36:56 PM
OK - here's a simple question. Has anyone got a Pentax Q (12MP, small sensor) and a 5Dc (12MP, FF sensor) - if we look at a comparison of the two, it should solve this issue once and for all, even though the 5Dc is using much older tech.

Why don't you just head over to DPReview or Imaging Resource and download studio files for the cameras you wish to compare? I would be careful with compact cameras because they will probably have sharpening even at 'neutral' settings.

As to crop vs FF: You will find FF a bit sharper. Until you run a sharpening pass on crop. The difference is there, but it doesn't amount to all that much at low to mid ISO. At high ISO crop cameras start to apply more NR, causing more blur, and post sharpening to compensate starts emphasizing noise.

Quote
The point of TrumpetPower's test is both of them are adjusted to a very low number of MP, therefore they're both on an equal footing (downsampling a high MP image to low MP is very similar to starting with low MP in the first place).

That's not even close to an equal footing. As good as our scaling algorithms are, scaling up is destructive while scaling down can actually yield more final detail then direct sampling at the lower resolution.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 24, 2013, 03:48:15 PM
But, if you have a choice between two cameras of different formats and different megapickles, go with the bigger format. (With, of course, the usual caveats that sufficient technology age can skew the results.)

Except 1D MK III vs 7D.

Oh wait, the 1D MK III ist two years older, I can't compare them ... 

Just joking... as you said, due to technology developments (and other reasons, as discussed) it doesn't make sense to compare sensors only in regard of size. (And likewise the whole thread doesn't make much sense IMO).

Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 03:49:06 PM
So, dtaylor, we have a test in which we have two images with the exact same number of megapickles, the exact same shutter speed, the exact same field of view, the exact same depth of field, the exact same sensor technology, better optics on the smaller sensor...and your point is that this is somehow an invalid comparison of two sensors with the same number of megapickles but different areas because of some magic resampling faery dust that made the image with the larger sensor become dramatically better than the image with the smaller sensor.

Just out of idle curiosity, had I performed the test with film -- you know, that plastic stuff with the smelly chemicals? -- would you still be maintaining that the test was somehow invalid because the enlarger has some sort of magic faery dust rendering the comparison simply invalid and horribly flawed?

Or, I have a better idea.

You're such an expert at this. How would you go about performing a comparison between two sensors with the same number of megapickles and the same sensor technology but different format sizes?

That is, after all, the question under discussion: does format size matter? So, how, exactly, would you hold all the variables constant except for format size?

Tell us your ideal experimental protocol.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 03:59:58 PM
Alan, I was being gracious in ignoring your complaint, as it indicates that you really don't understand even the simplest fact about what a crop sensor camera actually is. Specifically:

Alan's complaint was spot on. He very clearly understands what's going on.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 04:05:43 PM
But, if you have a choice between two cameras of different formats and different megapickles, go with the bigger format. (With, of course, the usual caveats that sufficient technology age can skew the results.)

Except 1D MK III vs 7D.

Oh wait, the 1D MK III ist two years older, I can't compare them ... 

Just joking... as you said, due to technology developments (and other reasons, as discussed) it doesn't make sense to compare sensors only in regard of size. (And likewise the whole thread doesn't make much sense IMO).

Eh, not exactly.

Until relatively recently, comparing formats was commonplace and trivial. The exact same film you loaded in a cartridge into your SLR was being used in large format backs. And you really had to be clueless in those days to insist that you could get the exact same quality out of the smaller format.

We've been in a rapid growth phase in the digital world where, in about a decade, we're seeing quality improvements comparable to what used to only be achieved by going with a larger format. The latest-and-greatest APS-C sensors have basically caught up with the earliest full-frame sensors. Those first full-frame sensors were going toe-to-toe with medium format film; today's full-frame kits outperform the view camera that Ansel Adams used -- and today's high-end medium format kits surpass anything anybody's ever had access to, perhaps with the exception of some of the insane custom setups.

However, there's very good reason to suspect that this age of rapid growth is just a phase, and that it won't be all that long (historically speaking) before it'll come to an end. Eventually, we'll be back to marginal improvements, and all camera sensors will have roughly the same pixel densities and noise characteristics and the like. When that day comes, once again, the defining characteristic will be format size, not sensor technology.

And we even see that to some extent today, within a manufacturer's lineup. Canon's currently-produced full-frame cameras outperform their currently-produced APS-C cameras by about a stop or so (what you'd expect), and the same is true with Nikon's full-frame v APS-C, and Sony's, and Leica's, and so on. Between manufacturers the lines aren't always so clear...but, then again, there were always wars between Kodak and Fuji films.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 24, 2013, 04:07:45 PM
@ TrumpetPower, on page 2 I posted four comparison pictures of 18MP APS and 21MP FF, shot at 100 ISO, subject close.

There is just no difference in sharpness, colour depth, tonal grad, shadow, - nothing.

You commented that you weren't surprised............
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 04:12:50 PM
Alan, I was being gracious in ignoring your complaint, as it indicates that you really don't understand even the simplest fact about what a crop sensor camera actually is. Specifically:

Alan's complaint was spot on. He very clearly understands what's going on.

He very clearly does not.

The question was whether two sensors with the same megapickles but different sizes would produce images of comparable sharpness.

There is only one way to test such a question: make two images using sensors of different sizes and the same number of megapickles. Which is exactly what I did.

You know, all y'all who think that sensor size has nothing to do with sharpness an only to do with noise or tonality or whatever are more than welcome to demonstrate otherwise. Complaining that magic resampling faery dust somehow introduced more sharpness into a test that was significantly stacked in favor of the loser isn't exactly all that impressive.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 04:22:32 PM
So, dtaylor, we have a test in which we have two images with the exact same number of megapickles,

False. From your test post:
Crop the wide image to the same field of view as the telephoto image, and scale the two to the same pixel dimensions.

You had two files with very different dimensions and then let a computer scale them. Computer generated pixels are not equal to directly sampled pixels. If they were, we could all shoot 1 MP sensors and scale to any print size we wanted.

I'm tired of debating your test. Your variables were all over the place, and it was basically a test of pixels on target and computer scaling, not of comparable FF/crop sensors. Yet you defend it like it was your child. Catching up on this thread I find you are actually being insulting to those who point out the test flaws. Grow up and try listening to them instead.

Quote
Just out of idle curiosity, had I performed the test with film -- you know, that plastic stuff with the smelly chemicals? -- would you still be maintaining that the test was somehow invalid because the enlarger has some sort of magic faery dust rendering the comparison simply invalid and horribly flawed?

It would be invalid for the same reason it's invalid now: fewer sampling points on target. It would just be grains instead of pixels.

Quote
You're such an expert at this. How would you go about performing a comparison between two sensors with the same number of megapickles and the same sensor technology but different format sizes?

Gee...I don't know...how about getting the actual cameras and putting the same lens on each; changing position to achieve the same FoV; and making sure that all other factors (scene; lighting; aperture; shutter; settings) are equal, thereby isolating the difference you want to measure (sharpness)?  ::)

On second thought...nah...that's just crazy talk  ;D
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 04:25:49 PM
There is only one way to test such a question: make two images using sensors of different sizes and the same number of megapickles. Which is exactly what I did.

Last I checked you used one sensor, two lenses, cropped one image resulting in fewer MP, then scaled up thinking that interpolated pixels = true MP.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 04:36:00 PM
@ TrumpetPower, on page 2 I posted four comparison pictures of 18MP APS and 21MP FF, shot at 100 ISO, subject close.

There is just no difference in sharpness, colour depth, tonal grad, shadow, - nothing.

You commented that you weren't surprised............

Yes, I wasn't surprised. You were comparing APS-C and 135 formats, which are only a stop apart, and latest-generation tech with first-generation tech. You found they were within a stop of each other. Of course! There's only a stop between the formats, and close to a stop of improvements the past decade.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 04:46:55 PM
If they were, we could all shoot 1 MP sensors and scale to any print size we wanted.

Ah. I see.

You really are that ignorant of the subject, no?

Scaling down is throwing away information. It's as if the information never existed, and the end result is the same as if you had never started with it in the first place.

Scaling up is inventing information. That information must come from somewhere. It's because there's no good place for that information that you can't upscale wantonly.

Quote
Gee...I don't know...how about getting the actual cameras and putting the same lens on each; changing position to achieve the same FoV; and making sure that all other factors (scene; lighting; aperture; shutter; settings) are equal, thereby isolating the difference you want to measure (sharpness)?  ::)

On second thought...nah...that's just crazy talk  ;D

Yes, that's crazy. Spectacular fail crazy.

Use the same lens on different formats and you get a different field of view. Change position and you get a different perspective in addition to a different field of view. Keep the aperture the same between different formats and you get different depth of field.

I was very specific in what I did and didn't change, and I did it for a reason. My test really was a true apples-to-apples comparison. The shooting position was the same, so the perspective was the same. The shutter speed was the same so the motion blur (not that there was any) was the same. The aperture was different, yes, but it resulted in the same depth of field. The ISO setting was different, yes, but it resulted in the same exposure -- and, unsurprisingly if you know the basics of photography, it resulted in basically the same amount of noise.

The only remaining variables were format size and sharpness. And, as is utterly unsurprising to anybody who knows as much about photography as you'd learn from an introductory textbook, the larger format captures more information per fraction of the frame, and thus a sharper image.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 04:48:20 PM
There is only one way to test such a question: make two images using sensors of different sizes and the same number of megapickles. Which is exactly what I did.

Last I checked you used one sensor, two lenses, cropped one image resulting in fewer MP, then scaled up thinking that interpolated pixels = true MP.

You checked worng.

The full-frame image was scaled down, not up. The small format image was a 100% crop.

And the small format image had a significantly superior lens.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 24, 2013, 04:59:43 PM
@ TrumpetPower, yes indeed, but that test was at close distance with large and easily defined subjects.

We took that camera on a shoot with 5D mk1, ( not the mk2 with which we did the test ) and out of interest shot the same frames on each camera. ( We stitch ). Although the 18MP 650 clearly had more resolution than the 13MP 5D, in the final picture, in the hills and woods behind our main subject, about quarter mile away, the ones from the 5D had more definition and a very subtle improvement in total graduation - what I refer to as "brio" in a picture. It is only a very very subtle difference but it is there.  I presume this is something to do with the fact that when dealing with far away subjects the actual image projected onto the FF sensor will be larger, and this, coupled with the larger pixels collecting more light give the benefit that isn't seem when making "test" shots of close subjects.

BTW, I wouldn't call a 5D Mk 2 first generation technology.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 24, 2013, 05:06:15 PM
It is perfectly obvious that a large format with a long focal length lens beats out a small format with the same number of megapixels with a short focal length lens, all things being equal, if they have the same field of view. But your "experiment" did not do that. Your set up had the long focal length lens with a narrow field of view and compared it with a short focal length with a wide field of view and then lost resolution from the small format by cropping.

Alan, are you serious?



Scenario a: two cameras, one with a 4.27mm x 6.4mm sensor and a 24mm lens, the other with a 24mm x 36mm sensor and a 135mm lens. Both sensors have 6.25µ pixels.

Scenario b: one camera with a 24mm x 36mm sensor with 6.25µ pixels. One image is made with a 24mm lens and cropped to only use the 4.27mm x 6.4mm central portion of the sensor; the other image is made with a 135mm lens and the full sensor.

Educate us: what, exactly, is the difference between those two scenarios?

Or are you somehow under the misimpression that lens focal length is a function of format size? Is that it? Do you think that a 24mm lens on a 4.27mm x 6.4mm sensor is still a wide-angle lens? If so, you need to brush up on your introductory optics. That small sensor would need a 4.27mm lens to produce the same field of view as a 24mm lens does on a 24mm x 36mm "full frame" sensor. That's why a 50mm lens is still a 50mm lens whether it's on a Rebel or a 5D, but it's a normal lens on the 5D and a telephoto on the Rebel. The lens hasn't changed, and it's still the exact same focal length as always, regardless of what camera you attach it to.

b&

Yes, I am serious. Although you claim in your customary gracious manner that I am clueless about sensors and optics, I do, in fact, know a little. The first is that crop sensors generally have much smaller pixels than larger sensors. For example, the Canon PowerShot G9 with its 7.6x5.7mm sensor has a pixel size of 2.5 µm compared with the 6.25 µm pixel 5D III. So your scenario with both large and small sensors having 6.25 µm is both false and irrelevant for the arguments in this forum because resolution depends, among other factors on pixel density or size.  The smaller size of the crop pixels goes to compensate for other factors and is crucial in any analysis.

Consider the following, which highlights the importance of pixel size and applies to a real scenario.  The height of an image I from object of height H a distance v away from the lens of focal length f for v>>f is I = H*f/v.  According to the Nyquist-Shannon sampling theorem and the Nyquist limit, I has to span ~2 pixels in order to be resolved. The 7D has a pixel size of 4.3 µM, so I has to be greater than 8.6 µm to be resolved. For the 5D III, I has to be >12.5 µm. For the same lens on a 7D and 5D III, f/v is the same for both at the same distance away and so I is the same. For the 5D III and a 100mm lens, two lines 3 mm apart cannot be resolved at distances greater than 24 metres. For the 7D and its crop sensor, the distance is 34.9 metres. So, between 24 and 34.9 metres, the 7D can resolve the two lines whereas it is optically impossible for the 5D III so to do.

It is your ignoring of the effects of pixel size (density) that invalidates your arguments.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 05:14:27 PM
Sporgon, I think I might be losing track of which cameras you're using for which test.

I would expect the original 5D to be somewhat but not hugely better than a latest-generation Rebel. I'm sure you couldn't tell the difference on an 8" x 10" print, and it'd be hard to tell the difference on anything you could print with a printer that would fit on your desktop. By 24" x 36", though, I'd expect the 5D classic to be better, but not earth-shatteringly so.

The 5DII will be significantly better at 24" x 36", but the Rebel is still going to make outstanding 24" x 36" prints. The bigger you go past 24" x 36", the farther the 5DIII is going to pull away from the Rebel...but both will make superlative billboards, of course.

For still life photography in good light, the difference between the 5DII and the 5DIII will be marginal, but the 5DIII cleans the 5DII's clock at action and low light photography.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 05:24:37 PM
The smaller size of the crop pixels goes to compensate for other factors and is crucial in any analysis.

The question isn't whether or not you can stack the deck in favor of a smaller format.

Build a larger format sensor with pixels of the same size as the larger smaller (sorry for the brain fart!) format, and all of your math is now irrelevant because the pixel pitch is identical.

The question is what role format size plays in image sharpness. You're ignoring that question and instead addressing what role pixel pitch plays in image sharpness. We all know that, all else being equal, a smaller pixel pitch will result in more sharpness. What most of the people here refuse to understand is that, when the pixel pitch is constant, all else being equal, the larger format will result in more sharpness.

Even beyond that, if the pixel pitch is adjusted such that the two formats have the same number of pixels and the larger format has that much of a larger pixel pitch, the larger format still results in more sharpness.

The only way that the sharper format can compete is with a substantial increase in sharpness, whether from a far smaller pixel pitch or newer technology (gapless microlenses, etc) or better optics or something else.

But, once again, as soon as you level the playing field and give the larger format the same pixel pitch and comparable optics and the rest, the larger format once again regains the sharpness edge.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: tortilla on January 24, 2013, 05:28:18 PM
Until relatively recently, comparing formats was commonplace and trivial. The exact same film you loaded in a cartridge into your SLR was being used in large format backs. And you really had to be clueless in those days to insist that you could get the exact same quality out of the smaller format.

And yet many people very shooting 35 mm film instead of large format, because it had it's own advantages. But I agree, in terms of IQ larger format is usually better.

Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 05:31:56 PM
The full-frame image was scaled down, not up. The small format image was a 100% crop.

My mistake when I typed that post.

You really are that ignorant of the subject, no?

I can't help but laugh at your asinine behavior. You really do believe that you know more then all the people pointing out the flaws, don't you?

Quote
Scaling down is throwing away information. It's as if the information never existed, and the end result is the same as if you had never started with it in the first place.

No, it's not. Scaling in either direction introduces a variable you can't compensate for. And in either direction final quality and sharpness depends on the algorithm and settings used. Go ahead and try scaling in PS with all the various choices. One of the things clearly affected by your choices is sharpness, the very thing you claim to be trying to isolate and test for.

Quote
Use the same lens on different formats and you get a different field of view. Change position and you get a different perspective in addition to a different field of view. Keep the aperture the same between different formats and you get different depth of field.

Perspective has nothing to do with sharpness at the plane of focus. DoF has nothing to do with sharpness at the plane of focus, and you want lens performance (related to aperture) to be identical. The test I described isolates one thing and one thing only: detail contrast related to format.

Your test isolated nothing. You've got different lenses, radically different apertures, radically different pixel-on-target counts, and an unknown scaling variable. Way to prove...absolutely nothing.

Quote
I was very specific in what I did and didn't change, and I did it for a reason.

And in doing so demonstrated your ignorance about how to isolate and test for a single variable.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: dtaylor on January 24, 2013, 05:37:10 PM
I would expect the original 5D to be somewhat but not hugely better than a latest-generation Rebel. I'm sure you couldn't tell the difference on an 8" x 10" print, and it'd be hard to tell the difference on anything you could print with a printer that would fit on your desktop. By 24" x 36", though, I'd expect the 5D classic to be better, but not earth-shatteringly so.

Canon's 18 MP APS-C sensor matches or exceeds their old 12 MP FF sensor in every respect. They're close, but the nod goes to the APS-C sensor.

Quote
The 5DII will be significantly better at 24" x 36", but the Rebel is still going to make outstanding 24" x 36" prints. The bigger you go past 24" x 36", the farther the 5DIII is going to pull away from the Rebel...but both will make superlative billboards, of course.

I've made large prints from the sensors in question. The 21 MP FF sensor is not significantly better than the 18 MP one at 24x36 at low to mid ISO. It doesn't get better as you go larger because it wasn't really better to begin with. Both sensors are good for roughly 24-30" when printing landscapes for critical review. Less demanding subjects and viewing conditions of course mean you can go larger with either. At high ISO the 21 MP FF sensor gains a very significant lead.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 24, 2013, 05:40:30 PM
The question we are dealing with here is "Is FF sharper than APS-C?" What you are arguing, Trumpetpower, is something different. It goes back to the old days of film where all cameras had the same sensor, emulsion. And everyone knows that a large format Hasselblad or a 2x2 Rolleiflex is better than 35 mm, which is better than 110. And a huge great plate camera would beat the lot. Of course a large sensor with the same size pixels as a small one is better.  I would love a 5D with a 46 megapixel sensor as it would make the 7D with its 18 megapixels redundant.  But, the fact is that we don't have that Canon yet and we are discussing Canon sensors. 
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 06:17:02 PM
I can't help but laugh at your asinine behavior. You really do believe that you know more then all the people pointing out the flaws, don't you?

There is no polite way to tell somebody, such as you, the level of ignorance and / or lack of intelligence displayed by repeatedly claiming that the Canon 135mm SF is sharper than the Canon TS-E 24mm II. I'm sorry, but your repeated insistence that my test is invalid because I used the sharpest lens on the market for the one, one of the softest lenses available for the other, and that said lens difference skewed the results, when the image made with the softer lens came out sharper...well, there really aren't any polite words to describe your position.

Quote
Scaling in either direction introduces a variable you can't compensate for. And in either direction final quality and sharpness depends on the algorithm and settings used. Go ahead and try scaling in PS with all the various choices.

That you've been on this kick clearly demonstrates that you've never done such an experiment, yourself.

Attached you'll find the results. The only significant difference, as one would expect, is the amplification of image noise in the nearest neighbor sample.

Indeed, your ignorance of the subject of scaling and sharpness is especially apparent here; anybody with experience in the matter knows that downsampling softens images, and that you need to apply a bit of sharpening to recover a bit of acutance. As with the lenses, you're arguing that something that skewed the results in favor of the small format somehow prejudiced the results against it.

Quote
Perspective has nothing to do with sharpness at the plane of focus.

Perspective has everything to do with photography.

Just try telling a real photographer that she's got to shoot her small format camera from a different position to maximize its sharpness compared with a larger format camera -- which is exactly what you're arguing for with your royally messed-up joke of an experimental protocol.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: iP337 on January 24, 2013, 08:11:29 PM
I'm glad to see a lot of people on this thread understand the differance between current APS-C and Full Frame sensors. :)

For those that still seem confused just go get a current full frame camera and go home happy with your sharp pics while pixel peeping ok :) now please stop posting in this thread.

For the more inquisitive minds trying to answer the topics question "Is Full Frame sharper than APS-C?"  First it's important that you understand when comparing images captured on 135 (it's not 135mm btw, it's just the cartrige size used for 35mm Photo film, I just find it easier to type "135" rather then "Full Frame 35mm") to images captured on APS-C (Advanced Photo System "Classic" created in 1996 "for High-Resolution photos") it's not the physical size of the sensor that matters it's the physical size of the individual pixel sensors that need to be compared.  So the question should REALLY be, "Are bigger pixels sharper than smaller pixels?"  the short answer to that is no but that depends on how you use it.

For example, there is no point to compare 2 pictures at 50mm and at 35mm that were taken on the same camera; if you crop the 35mm to the FoV of the 50mm and blow it up to the same size as the 50mm than it will obviously be softer because they both had the same individual pixel sizes and therefore the same "resolving" power, one just got blown up to 150% compared to the other at 100%. 

Back in the film days the grain size was tied to ASA speed (aka ISO), smaller grain (or faster ASA) also meant sharper finer details. In Digital photography there is no grain size, we now have pixel size and it is not tied to the ISO speed anymore, it's tied to resolution and sensor size. Current APS-C cameras have smaller/finer individual grain/pixel sensors than their 135 counterparts, think of it like the D800 vs the 5D3, so you need to compare them by "pixel size" not sensor size.  Unfortuantely lenses made to be sharp on 135 don't care about resolving enough for the finer pixels of new APS-C sensors, this is why Canon is updating all their lenses.  We are reaching a point where the lenses are becoming the bottleneck to image sharpness.

Of course smaller pixels have other issues such as light-gathering and dynamic range but new technologies such as gapless microlenses and back illiminated pixels are helping to boost these issues.

Oh and thanks for pointing out the 1Dx doesn't have a crop mode, I missed that,  but the 1Dc video and Nikon Full Frame cameras have crop modes.
"...The 1D C offers 4K (4,096 x 2,160 pixels) video capture with an APS-H crop. You can also opt for a Super 35mm crop mode, ..."
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 08:38:08 PM
Current APS-C cameras have smaller/finer individual grain/pixel sensors than their 135 counterparts, think of it like the D800 vs the 5D3, so you need to compare them by "pixel size" not sensor size.

If there's one thing this thread has conclusively demonstrated, it's the wisdom of the marketing departments at latching on to and perpetuating the megapickle myth...if it persists so strongly here, amongst a bunch of gearheads who damned well should know better and in spite of concrete evidence otherwise, you just know that the general public doesn't stand a chance.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: serendipidy on January 24, 2013, 08:56:15 PM
I have done extensive testing in my kitchen and I can categorically confirm that a brand new Kyocera Ceramic Knife is sharper than either a Full Frame or APS-C camera ;D
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: iP337 on January 24, 2013, 08:59:44 PM
hope this helps:

http://www.minasi.com/photos/dslrmag/ (http://www.minasi.com/photos/dslrmag/)
Quote
"The Missing Piece:  Sensor Resolution

Clearly there's the two sensors have other differences besides size.  To see that, let's do a bit of arithmetic.  Canon says that the 5D sensor holds 12.8 megapixels, and the 30D sensor holds 8.2 megapixels.  An APS-C sensor is 17 mm x 25 mm, which is 425 mm2.  A full frame sensor is 24 mm x 36 mm, which is 864 mm2.  Aha!  The full frame sensor has about twice the square millimeters' area of the APS-C sensor, but only about 1.5 times the number of pixels.  Calculating the resultant average size of a 5D "megapixel" and a 30D "megapixel," we get

5D pixel size = 864 mm2 / 12.8 million pixels = 68 mm2 per million 5D pixels

30D pixel size = 425 mm2 / 8.2 million pixels = 52 mm2 per million 30D pixels

The 5D pixels, then, are a bit larger, making for a somewhat lower-resolution image.  It's almost as if the 30D has finer grained film than the 5D.  The field of view on the 30D isn't as large, but it can capture any given thing in the field of view better than the 5D can.  Thus, if we were taking telephoto pictures of, say, birds in a nest, then the 30D would provide a somewhat better image than would the 5D.

This apparently isn't the case for all full frame sensors, however.  For example, when I looked up the megapixel values for the EOS-1Ds and the EOS-1Ds Mark II, I found that they offered 11.1 and 16.7 megapixels, respectively.  That would imply that the an EOS-1Ds megapixel would be 78 mm2 in size, worse grain than that offered by the 5D, and the Mark II's megapixel is only 52 mm2, equaling the 30D.

To sum up, then:


Full frame digital SLRs will always photograph a significantly larger field of view than will an APS-C digital SLRs
APS-C digital SLRs may, however, offer finer resolution in their sensors, meaning that they may be the better choice for telephoto applications wherein the subject is too far away to fill even an APS-C's field of view.  The only way to be sure is to compute size of a "megapixel" by dividing a sensor's megapixel count by either 425 (for an APS-C sensor) or 864 (for a 35mm full frame sensor); smaller numbers mean finer "grain" and better images.
These aren't the only factors to consider about applicability of a given camera for a given usage.  For example, the single most important factor in getting that rare shot of the vermillion-eared grubcatcher may be how quickly your camera auto-focuses!"

Basically with the large pixels of Full Frame cameras can get a wide dynamic range which of course means a lower contrast and at the sake of finer details but the pixel sizes on APS-C we get a narrower dynamic range which means higher contrast and also finer details.  It's exactly like choosing ASA back in the film days, slower ASA speeds (lower number) means sharper image but less sensative to light and faster ASA (higher number) means low light at the sake of fine detail sharpness.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:00:21 PM
Now I have difficulties to understand what you mean,  going for  higher resolution is that a myth? or not good?

Mikael, the megapickle myth says that megapickles are all that contribute to a camera's image quality. It says that an 18 megapickle 1/2.3" P&S camera like the Sony WX150 produces images 160% sharper than an 11 megapickle full frame camera like the original 1Ds.

It is, in short, the exact same "stuff and nonsense," as Joe Biden might put it, that everybody arguing with me has been spewing.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:19:24 PM
hope this helps:

http://www.minasi.com/photos/dslrmag/ (http://www.minasi.com/photos/dslrmag/)
Quote
Thus, if we were taking telephoto pictures of, say, birds in a nest, then the 30D would provide a somewhat better image than would the 5D.

This is only true in the rare case where you're so distance limited that you're cropping even on the 30D. And, in that case, you're no longer comparing 135 to APS-C, but rather two sensors of effectively the same size of something rather smaller than even APS-C -- and the two same-sized sensors have different resolutions. It should therefore be no surprise that the higher-resolution sensor of the same physical size produces sharper images.

But when you're not distance-limited, when you can fill the frame with your subject with a lens suited to the format -- such as when you've got a 300 f/2.8 on the 30D and a 500 f/4 on the 5D -- the 5D is going to produce substantially better results. That's even true in (most) instances where the 135 format camera has fewer megapickles than the APS-C camera.

Quote
Basically with the large pixels of Full Frame cameras can get a wide dynamic range which of course means a lower contrast and at the sake of finer details but the pixel sizes on APS-C we get a narrower dynamic range which means higher contrast and also finer details.  It's exactly like choosing ASA back in the film days, slower ASA speeds (lower number) means sharper image but less sensative to light and faster ASA (higher number) means low light at the sake of fine detail sharpness.

Erm...the point you're missing is that the exact same film in a larger format camera produces sharper images. Not only that, coarsely-grained film in a large format camera still produces sharper images than fine-grained film in a small format camera.

And you're also missing the point that the exact same principle holds true today with digital. Sure, to keep costs down, manufacturers don't use the same extreme pixel densities in their larger format cameras as in the small ones. But, if they were, you'd get the double benefit of both larger format size and higher-resolution sensors.

Once again, there are two variables: format size and sensor resolution (aka "megapickles"). And, of the two, format size is generally more important to sharpness than sensor resolution -- though, of course, sufficient disparities between the two can eventually tip the scales the other way, as we're finally starting to see the best and newest of the APS-C cameras catching up with the oldest of the 135 cameras.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:21:50 PM
Now I have difficulties to understand what you mean,  going for  higher resolution is that a myth? or not good?

Mikael, the megapickle myth says that megapickles are all that contribute to a camera's image quality. It says that an 18 megapickle 1/2.3" P&S camera like the Sony WX150 produces images 160% sharper than an 11 megapickle full frame camera like the original 1Ds.

It is, in short, the exact same "stuff and nonsense," as Joe Biden might put it, that everybody arguing with me has been spewing.

Cheers,

b&

More megapixels = better picture quality,better tonal transitions and less estimation errors and jaggies, easier to correct CA etc .  Here, a discussion, read John Sheehy, Eric Fossum , the father of the active cmos , this subject has been discussed many times http://forums.dpreview.com/forums/post/37445608 (http://forums.dpreview.com/forums/post/37445608)

If all else is equal, yes.

But the whole subject of the thread is format size, not megapickles -- and it takes a metric fuckton of megapickles to surpass a change in format size.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:30:41 PM
What all else?

Specifically, in this case, format size.

But one can also imagine all sorts of other technological improvements independent of pixel density. Improved signal processing, capturing multiple wavelengths per photosite (like the Foveon), that sort of thing. Perhaps even an hybrid optical solution with another element in the body in the place of the focal plane that magnifies the image onto an oversized sensor.

Any of those sorts of things could conceivably result in a sensor with a certain number of megapickles that outperforms one with the same or even more megapickles.

Thus, the caveat. If everything is identical between two sensors except for the megapickle count, the one with the megapickle count will win. But if any of a number of other factors is in favor of the sensor with fewer megapickles, you'd have to examine how all the variables add up to figure out which actually wins.

And the most common of those factors, and the one which almost always trumps megapickles by a lot, is format size.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:36:00 PM
More megapixels is always  better = better picture quality,better tonal transitions and less estimation errors and jaggies, easier to correct CA etc .  Here, a discussion, read John Sheehy, Eric Fossum , the father of the active cmos , this subject has been discussed many times , its is funny when people like to tell Eric Fossum how a sensor works.  http://forums.dpreview.com/forums/post/37445608 (http://forums.dpreview.com/forums/post/37445608)

Is it therefore your assertion that the 18 megapickle Sony WX150 produces better images than the 11 megapickle Canon 1Ds?

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 09:42:59 PM
no, go back to my answer again, I added sensor area because I know that this question was coming, more pixels ia always better and a larger sensor area is always better, it means more pixels

Mikael, you really should use the preview function. Changing your posts, especially after people have replied to them, is rude. It falsely makes other people look like they're arguing against a straw man when all they're doing is responding to something you've already realized is in error -- and it also makes it look like you never made the error in the first place, which is a lie.

If you really must change something after the fact, leave the original, strike it out (EDIT: to clarify, use strikethrough), and add something like, ``EDIT: Sorry, that's a mistrake. I really should have written...''

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 24, 2013, 10:13:23 PM
I know that this question was coming, more pixels ia always better and a larger sensor area is always better, it means even more pixels.

As I have already demonstrated, even when both formats have the exact same number of megapickles, the larger format still wins.

The smaller format needs not merely an equal number of pixels, not only an equal pixel density (and therefore more megapickles), but something even more in addition to all that in order to produce the same image quality as a larger format. That could be a more efficient sensor, it could be better optics, it could be even more megapickles, it could be any number of things.

But what sets larger formats apart from smaller ones isn't the number of megapickles but rather the simple geometry of a larger imaging area capturing more information and resulting in a smaller enlargement from capture (sensor / film) size to display size.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 24, 2013, 11:53:02 PM
Gee...I don't know...how about getting the actual cameras and putting the same lens on each; changing position to achieve the same FoV; and making sure that all other factors (scene; lighting; aperture; shutter; settings) are equal, thereby isolating the difference you want to measure (sharpness)?  ::)

On second thought...nah...that's just crazy talk  ;D

Yes, that's crazy. Spectacular fail crazy.

Use the same lens on different formats and you get a different field of view. Change position and you get a different perspective in addition to a different field of view. Keep the aperture the same between different formats and you get different depth of field.

I was very specific in what I did and didn't change, and I did it for a reason. My test really was a true apples-to-apples comparison. The shooting position was the same, so the perspective was the same. The shutter speed was the same so the motion blur (not that there was any) was the same. The aperture was different, yes, but it resulted in the same depth of field. The ISO setting was different, yes, but it resulted in the same exposure -- and, unsurprisingly if you know the basics of photography, it resulted in basically the same amount of noise.

I thought at some point in this long, acrimonious thread, AlanF (but maybe someone else) commented that TrumpetPower had failed to isolate the relevant variable.  That's true - way to many differences in this 'test'.

"Spectacular fail crazy."  No, dtaylor is spot on.  I seem to recall that several pages back, TrumpetPower stated that the thing to do would be to use two sensors of the same MP count but different sizes, that's at least barking up the right tree, however, the 'test' didn't do that.

Evaluating sensor sharpness using two different lenses at different apertures? Scaling the resulting images? That's uber-spectacular quintuple-facepalm-type fail. 

TrumpetPower asked what the ideal test would be...first off, not his.  ::)  The solution is the one dtaylor suggested - two cameras, one FF, the other APS-C, with the same MP count.  Use the same lens, and change the distance to match the FoV. As for the objections of problems with changing distance resulting in different perspective and the same apertures resulting in different DoF on different formats, there's an obvious solution: a flat target, parallel to the sensor. That means no perspective to be altered (perspective alters the apparent distance relationship between subjects at different distances, but with a flat target the entire subject is at a fixed distance), and the flat target renders DoF moot.

So...two equal MP sensors of the same generation, a flat target framed identically, same lens for both (preferably a sharp one), same aperture.  Where, oh where, could one find such a test? How about here (http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=458&Camera=779&Sample=0&FLI=0&API=2&LensComp=458&CameraComp=808&SampleComp=0&FLIComp=0&APIComp=2).

What's the conclusion?  Pretty much this:

...all other factors being equal...and I've always found the same thing: FF is sharper out of camera, but the range is small enough to be closed by bumping up sharpening in camera or post. When the sensors are otherwise comparable of course.

Is this a perfect test?  No - there's no such thing with the tools available. The AA filters are different (the 18 MP 7D fares much worse in the above TDP comparison than the T4i, for example, likely due to a stronger AA filter), the firmware is different, etc.  It's a test at one distance per camera, at some distances with some targets the Nyquist sampling issues raised by AlanF are a determining factor. It's a test at ISO 100 - at ISO 3200, the results would be quite different. 

Bottom line - the differences of opinion in this thread far exceed the real differences in sharpness between sensor formats, and the wagging tongues in this thread are sharper than my Wüsthof cutlery.   :P   

Over and out, for me.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 01:31:12 AM
The solution is the one dtaylor suggested - two cameras, one FF, the other APS-C, with the same MP count.  Use the same lens, and change the distance to match the FoV. As for the objections of problems with changing distance resulting in different perspective and the same apertures resulting in different DoF on different formats, there's an obvious solution: a flat target, parallel to the sensor. That means no perspective to be altered (perspective alters the apparent distance relationship between subjects at different distances, but with a flat target the entire subject is at a fixed distance), and the flat target renders DoF moot.

You might have a point...if we were comparing photocopiers.

But you, of all people, should know that the results of, say, three portraits, one made with APS-C, one with 135, and one with 645, all with a 50mm lens at the same aperture and "zoomed" with the feet, will be so radically different that any photographer who suggested they were somehow interchangeable would be fired on the spot for gross incompetence and laughed off the set. Try that as a sports photographer and you'll be ejected from the venue by security. Try it as a landscape photographer and you'll fall off the cliff to your death.

I cannot imagine a more pointless, unrealistic test. If your goal is to demonstrate a passion for creating the ultimate rig for imaging newspapers taped to brick walls, congratulations, you've succeeded. But if your goal was to demonstrate an understanding of actual photography as practiced by actual photographers....

Again, the test I performed resulted in two images with the same number of pixels in addition to the same perspective and depth of field and background magnification and out-of-focus blur and everything else a photographer cares about. The only variable was format size, and we saw that sharpness is very closely related to format size and not at all related to the number of pixels in the image. All your test demonstrates is that, if you ignore everything that actually defines what an image of anything other than a test chart looks like, you can get two systems with certain similar specifications to make similar images of a test chart and nothing else.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 25, 2013, 06:08:04 AM
I cannot imagine a more pointless, unrealistic test. If your goal is to demonstrate a passion for creating the ultimate rig for imaging newspapers taped to brick walls, congratulations, you've succeeded. But if your goal was to demonstrate an understanding of actual photography as practiced by actual photographers....

Again, the test I performed resulted in two images with the same number of pixels in addition to the same perspective and depth of field and background magnification and out-of-focus blur and everything else a photographer cares about. The only variable was format size, and we saw that sharpness is very closely related to format size and not at all related to the number of pixels in the image. All your test demonstrates is that, if you ignore everything that actually defines what an image of anything other than a test chart looks like, you can get two systems with certain similar specifications to make similar images of a test chart and nothing else.

Therein lies your problem. Your test attempted to compare 'the same picture'.  You might have a point...if that were the goal. But we're not asking about 'everything that defines an image', we're asking about only one thing.  Let's revisit the title of this thread: Is FF sharper than APS-C?  Not 'does FF take a better picture'.  Yes, photographers care about 'better pictures' but that's not what's being asked here.  Only sharpness.  So in this case, taking pictures of a newspaper taped to a brick wall would be a far more appropriate test of the question than yours.

"The only variable was format size..."  Really?  Do you understand what a variable is?  Do you know the difference between a dependent variable and an independent variable, and how to tell when a dependent variable becomes a confounding variable?  You used different lenses to take the different pictures. You processed the images differently.  We call those confounding dependent variables.  Your test was not designed to answer the question, and therefore was flawed for the purpose at hand. 

"...the test I performed resulted in two images with the same number of pixels in addition to the same perspective and depth of field and background magnification and out-of-focus blur..." Guess what?  So did the TDP comparison I linked. Same number of pixels (but achieved without scaling), same effective perspective (indeterminate because the image has no depth), same effective depth of field (essentially none, as the entire subject is within it), same background magnification (none, no background), same OOF blur (none, everything in focus).  Unlike your test, the TDP ISO 12233 crop holds everything constant.  It's no accident they're called that - ISO 12233 is the "standard for measuring the resolution of electronic still imaging," and that's what we're talking about here...not 'better picture', sharpness.

An analogy: It's as if I asked, "What is the sodium content of french fries vs. carrot sticks?" Your test is trying to answer a question like 'which one tastes better?''  Yes, that's an important question for a person who wants a snack, but that's not what's being asked.  I'm looking for a chemical analysis of Na+ content, and you are conducting a blind taste test.  Interesting and informative, perhaps, but a complete fail as far as answering my question.

If you want to test the effect of sensor format on sharpness, you must hold everything else constant - especially the lens and the post processing. You varied both.  It's not that your test was invalid per se, but rather that it was not designed to address the question being asked.  Sharpness is just one component of picture quality, but again - that's the one we want to test.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 09:57:23 AM
Let's revisit the title of this thread: Is FF sharper than APS-C?  Not 'does FF take a better picture'.  Yes, photographers care about 'better pictures' but that's not what's being asked here.  Only sharpness.  So in this case, taking pictures of a newspaper taped to a brick wall would be a far more appropriate test of the question than yours.

Again, such would be a valid complaint amongst photocopier repair techs.

But, ask any working photographer if it makes any sense to compare sharpness of two photographs of a real-world scene with dramatically different compositions, perspectives, depths of field, amounts of background blur, and all the rest, and they'll think you're either completely nuts or one of those crazy Internet measurebators who only takes pictures of newspapers taped to brick walls -- as if there's a difference.

In the context of a photography discussion, the question most reasonably should be considered to be, "Does 135 make sharper photographs than APS-C?" Not, "Does 135 make sharper photocopies than APS-C?"

Quote
Your test was not designed to answer the question, and therefore was flawed for the purpose at hand.

Physician, heal thyself.

I'll even concede the point that 135 and APS-C make comparable photocopy platforms.

Now, which system produces sharper photographs?

Quote
Do you know the difference between a dependent variable and an independent variable, and how to tell when a dependent variable becomes a confounding variable?  You used different lenses to take the different pictures.

Yes, I do know what a confounding variable is. And the fact that you led off with the different lenses demonstrates that you don't.

The hypothesis is that image sharpness is independent of sensor format, and that two formats with the same total pixels will produce images of the same sharpness. The experimental results falsified that hypothesis, even -- nay, especially though the choice of lenses is known to have biased the results in the opposite direction.

If your hypothesis is that John and Sue can both run as fast, and you then make Sue but not John carry a 25 pound sack of potatoes around the course, and if Sue still manages to easily beat John, then you know that Sue is definitely the faster runner. You don't know how much faster a runner she really is, but you definitely know that she's a faster runner.

Had John won, you wouldn't know if he won because he's a faster runner or if it's because Sue was saddled with all those potatoes. Had they tied, you'd know that Sue was the faster runner, and that the difference in performance is equal to a sack of potatoes.

But neither scenario is what happened. What we found is that, even when we weigh down Sue with a sack of potatoes, she still crosses the finish line well before John.

And now you understand how confounding variables work, and why my choice of lenses makes the point more emphatic.

...unless, of course, it is your position that the 135 SF is actually sharper than the TS-E 24 II, but I rather doubt you'd be capable of such cluelessness.

Now, go through all of my other variables, and you'll find the same applies: they're tilting the scales, yes, but in favor of the smaller format. In addition to the sack of potatoes in the form of a "meh" lens compared with a legendary one, the larger format also got weighed down with even more sacks of potatoes in the form of aperture (f/4 v f/32), ISO (100 v 6,400), and post-processing (SOC v unsharpened resampling).

Again, if the small format had turned out sharper or comparable, we would have a hard time making a conclusion. But that's not what happened. Even after we loaded down the larger format with all those sacks of potatoes, it still crossed the finish line first.

So, my test can't tell you how much sharper the larger format is, but it most emphatically does tell you that the larger format actually is sharper.

(Even if they're equally lousy photocopiers.)

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 25, 2013, 10:23:03 AM
...my test can't tell you how much sharper the larger format is, but it most emphatically does tell you that the larger format actually is sharper.

So do the ISO 12233 crop comparisons. That just goes to show that even a poorly designed experiment which includes both intentional biases (different lenses shot at different apertures) and unequal data manipulation (image scaling), can yield a correct result...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 10:49:01 AM
...my test can't tell you how much sharper the larger format is, but it most emphatically does tell you that the larger format actually is sharper.

So do the ISO 12233 crop comparisons. That just goes to show that even a poorly designed experiment which includes both intentional biases (different lenses shot at different apertures) and unequal data manipulation (image scaling), can yield a correct result...

Once again, you're comparing photocopiers, not cameras.

The comparison between a Sony WX150 and a 1Ds would most emphatically not be with a lens of the same focal length on each. The Sony lens has a focal length of about 4.5mm - 45mm. I've never even heard of a 4.5mm lens for EF mount.

No, you'd set the Sony at the ends and middle of its range, and either use a superzoom on the Canon or grab a couple / few lenses with comparable fields of view.

Now, do you agree that that's how you'd go about comparing the images produced by those two cameras? Or would you shoot the Canon (somehow) at 4.5mm with the lens pressed up against the test chartt?

In other words, are you a photographer, or are you a photocopyist?

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 25, 2013, 12:23:58 PM
The comparison between a Sony WX150 and a 1Ds would most emphatically not be with a lens of the same focal length on each. The Sony lens has a focal length of about 4.5mm - 45mm. I've never even heard of a 4.5mm lens for EF mount.

I will repeat the topic at hand, one more time, please read carefully: Is Full Frame sharper than APS-C?  Does the Sony camera that you keep bringing up have an APS-C sensor in it?  If it does, we could discuss how to compare that camera's sensor to a Canon full frame sensor.  If it doesn't, such a test would be tangential, irrelevant, and yet another test that fails to answer the question being asked. Exactly like your test…

To be honest, this thread is starting to smell a lot like another recent thread, with the part of 'intransigent, insult-delivering antagonist' played by a different actor, only the insults are more frequent and rude and there's apparently not even the excuse of a language barrier in your case.  Accordingly, given that my normal limit is one such 'debate' per week, I'm done.   If it would help your ego to view this as a forfeit on my part, and you want to infer that means your inappropriate 'test' was somehow a properly relevant one, you go right ahead. 

干杯 (or gānbēi, if you can't read Mandarin - pinyin is easier to Google  ;) )
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 25, 2013, 12:50:12 PM
sorry for the brain fart!

Apologies accepted!
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 01:35:06 PM
The comparison between a Sony WX150 and a 1Ds would most emphatically not be with a lens of the same focal length on each. The Sony lens has a focal length of about 4.5mm - 45mm. I've never even heard of a 4.5mm lens for EF mount.

I will repeat the topic at hand, one more time, please read carefully: Is Full Frame sharper than APS-C?  Does the Sony camera that you keep bringing up have an APS-C sensor in it?  If it does, we could discuss how to compare that camera's sensor to a Canon full frame sensor.  If it doesn't, such a test would be tangential, irrelevant, and yet another test that fails to answer the question being asked. Exactly like your test…

Obviously, the Sony has an even smaller sensor still.

You really should be aware of this but obviously aren't because you're belaboring the point, but, when comparing a specific case with marginal differences, it is often very helpful to compare the general case with greater differences.

I would hope that you'd agree that an hypothetical 20 megapickle 1/2.3" camera would be nowhere near as sharp as an equally-hypothetical 20 megapickle 8x10 digital view camera.

I would also hope that you'd agree that, when comparing those two cameras, you would not compare them both with the same lens -- that is, with a 4mm lens on the small format camera as well as a 4mm lens on the view camera. Rather, you'd use a 4mm lens on the small camera and a 180mm lens on the large camera. Otherwise, to maintain the same magnification of the subject, the subject would probably have to be a negative distance from the front of the large format camera's sensor.

Can we agree on that? Yes? Please?

Let's continue the thought experiment.

Rather than compare 1/2.3" and 8x10, let's compare 4/3 and 645. Here, you might use a 24mm lens on 4/3 and a 100mm lens on 645. 24mm is a normal lens on 4/3, but it's a 180° fisheye on 645.

Still with me?

Just to recap: when comparing 1/2.3" and 8x10, it's probably physically impossible to use the same focal length lens at the same subject magnification on both. You can physically do such a comparison between 4/3 and 645, but the results are nowhere near similar, even at a first glance by a non-photographer.

If the subject were, "Is 8x10 sharper than 1/2.3"?" or if it were, "Is 4/3 sharper than 645?" would you consider your protocol valid? Hell, would it even occur to you to use such a protocol? I would really hope not.

So, now, we finally move to a comparison of APS-C and 135.

Can you offer a rational explanation as to why an experimental protocol that's physically impossible in one setting and laughably absurd in another would suddenly become valid in a third setting merely because the variables are close enough that you can fudge them to kinda sorta fit if you pick just the right type of never-happens test?

Again, my test simulates what actual photographers actually do when actually making photographs. You pick your subject, figure out the ideal perspective and composition, pick a lens with a field of view that suitably frames it, pick an aperture that creates a certain depth of field, pick a shutter speed that captures motion suitably, leaving you with hoping that the resultant ISO is within your camera's acceptable range, else you start making compromises to the other variables. Once you've got all that set, if you were going to compare your results with a different camera, you'd want the same composition, the same framing, the same depth of field, and the same shutter speed if at all possible. If you can achieve all that and the ISO is in the camera's range, you've got your apples-to-apples comparison. Swap the two cameras and the only difference is in the image quality inherent in the two systems. (If not, the necessary compromises are a mark against the camera that can't keep up. We haven't even mentioned DoF; my experiment was at the almost-not-overlapping extremes of available DoF between the two formats -- you could get much shallower DoF out of the large format and much deeper DoF out of the smaller format.)

TL/DR: again, your protocol is valid for photocopiers. Mine is valid for photographers.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 25, 2013, 02:21:57 PM
You're still not answering the question.  I read your posts and it's like, which is sharper, the 5D Mark III with the 35 f/2 lens, or the 7D with the 16-35L II lens set at 22mm.  Who cares?  That doesn't answer which sensor is sharper. 
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 02:57:49 PM
You're still not answering the question.  I read your posts and it's like, which is sharper, the 5D Mark III with the 35 f/2 lens, or the 7D with the 16-35L II lens set at 22mm.  Who cares?  That doesn't answer which sensor is sharper.

Are we comparing silicon chips set up to poorly mimic photocopiers, or are we comparing camera systems used to make photographs?

See, i was under the impression that this is a gathering place for photographers, and that photographers would know that one matches lens focal length to format. Thus, the understanding would be that a comparison between APS-C and 135 wouldn't be of one isolated component in the camera, but rather of the whole system -- a true comparison of 135 format with APS-C format. And, as such, you'd compare an APS-C camera with a normal lens to a 135 camera with a normal lens. And, as all photographers should know, a normal lens is defined as one with a focal length roughly the same as the diameter of the imaging area -- 43mm for 135, and 27mm for APS-C. (And 7mm for 1/2.5", 300mm for 8x10, and so on.) What you wouldn't do is compare APS-C with a short telephoto lens (50mm) to 135 with a normal lens (also 50mm). Even if you could physically mount the same lens to both cameras. You certainly wouldn't compare 1/2.5" with a long telephoto lens (50mm) against APS-C with a short telephoto lens (50mm) against 135 with a normal lens (50mm) against a physically impossible 270° fisheye lens (50mm) on 8x10.

But, no. Apparently this is a gathering place for some very confused photocopy techs who think that "photographic sharpness" has something to do with how well you can adapt one isolated component of a camera to serve as a woefully inadequate photocopy machine. My mistrake....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 25, 2013, 03:03:18 PM
14 pages later, how hard is it to believe that FF is sharper than APS-C?  ???
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 25, 2013, 03:48:24 PM
You're still not answering the question.  I read your posts and it's like, which is sharper, the 5D Mark III with the 35 f/2 lens, or the 7D with the 16-35L II lens set at 22mm.  Who cares?  That doesn't answer which sensor is sharper.

Are we comparing silicon chips set up to poorly mimic photocopiers, or are we comparing camera systems used to make photographs?

See, i was under the impression that this is a gathering place for photographers, and that photographers would know that one matches lens focal length to format. Thus, the understanding would be that a comparison between APS-C and 135 wouldn't be of one isolated component in the camera, but rather of the whole system -- a true comparison of 135 format with APS-C format. And, as such, you'd compare an APS-C camera with a normal lens to a 135 camera with a normal lens. And, as all photographers should know, a normal lens is defined as one with a focal length roughly the same as the diameter of the imaging area -- 43mm for 135, and 27mm for APS-C. (And 7mm for 1/2.5", 300mm for 8x10, and so on.) What you wouldn't do is compare APS-C with a short telephoto lens (50mm) to 135 with a normal lens (also 50mm). Even if you could physically mount the same lens to both cameras. You certainly wouldn't compare 1/2.5" with a long telephoto lens (50mm) against APS-C with a short telephoto lens (50mm) against 135 with a normal lens (50mm) against a physically impossible 270° fisheye lens (50mm) on 8x10.

But, no. Apparently this is a gathering place for some very confused photocopy techs who think that "photographic sharpness" has something to do with how well you can adapt one isolated component of a camera to serve as a woefully inadequate photocopy machine. My mistrake....

b&

Then start your own thread, because this thread ISN'T about any of that.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 04:11:48 PM
Then start your own thread, because this thread ISN'T about any of that.

ORLY?

Where, exactly, did NormanBates express a desire to use his cameras as a rich man's bad photocopier?

Indeed, the whole point of his original post was that he wanted to spend his money on the sharpest photographic system.

Of course, he did his tests by poorly photocopying dollar bills. Fortunately for him, his test wasn't so deeply flawed as to reach the worng conclusion.

Indeed, NormanBates, if you're still hanging in there, I would suggest doing some tests with a still life scene rather than a dollar bill. Set it all up with the 90 on the 5DII, get everything all nicely framed, and glue the tripod (and the tabletop!) to the floor. Shoot the scene at several apertures and adjust ISO to keep exposure constant. (You can do the same but adjust shutter speed, of course...but you'll find the results more informative if you keep shutter speed constant.) Then, leave the tripod alone and swap the 5DII with the 90 for the 550D with the 50 and repeat the experiment, being sure to use the same combinations of shutter speed and aperture, with an overlapping range of apertures to capture the same depth of field and background magnification with both camera systems.

That way, you'll be comparing 135 format with a short telephoto to APS-C with a very similar short telephoto -- exactly as you'd do in the real world if you were, say, doing a comparison with a portrait shoot. You wouldn't use a 50 for both shots and shove the camera up the model's nose with the 135 format, so why perform your test that way?

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: zim on January 25, 2013, 04:53:26 PM
Is Full Frame sharper than APS-C?

http://www.youtube.com/embed/lKR-AKLM3HQ (http://www.youtube.com/embed/lKR-AKLM3HQ)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 25, 2013, 05:22:12 PM

To be honest, this thread is starting to smell a lot like another recent thread, with the part of 'intransigent, insult-delivering antagonist' played by a different actor, only the insults are more frequent and rude and there's apparently not even the excuse of a language barrier in your case.  Accordingly, given that my normal limit is one such 'debate' per week, I'm done.   If it would help your ego to view this as a forfeit on my part, and you want to infer that means your inappropriate 'test' was somehow a properly relevant one, you go right ahead. 


Hi TrumpetPower! Are you the same TrumpetPower! who writes in Wikipedia and is discussed in http://en.wikipedia.org/wiki/User_talk:Paul_Barlow/Archive_2 (http://en.wikipedia.org/wiki/User_talk:Paul_Barlow/Archive_2)  where it is written:

“Hello, I don't know if you agree, but imo TrumpetPower! seems to be reaching a point of obnoxiousness that might warrant some kind of action. Any thoughts? john k 20:49, 23 March 2006 (UTC)”
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 05:53:45 PM

To be honest, this thread is starting to smell a lot like another recent thread, with the part of 'intransigent, insult-delivering antagonist' played by a different actor, only the insults are more frequent and rude and there's apparently not even the excuse of a language barrier in your case.  Accordingly, given that my normal limit is one such 'debate' per week, I'm done.   If it would help your ego to view this as a forfeit on my part, and you want to infer that means your inappropriate 'test' was somehow a properly relevant one, you go right ahead. 


Hi TrumpetPower! Are you the same TrumpetPower! who writes in Wikipedia and is discussed in http://en.wikipedia.org/wiki/User_talk:Paul_Barlow/Archive_2 (http://en.wikipedia.org/wiki/User_talk:Paul_Barlow/Archive_2)  where it is written:

“Hello, I don't know if you agree, but imo TrumpetPower! seems to be reaching a point of obnoxiousness that might warrant some kind of action. Any thoughts? john k 20:49, 23 March 2006 (UTC)”

Really? You have nothing better to add to the discussion than to dig up a 27-word seven-year-old comment on a person's private Wikipedia space complaining about my participation in an edit war on an article on a religious topic, and to post it to a discussion on a Canon rumors forum?

Okay....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 25, 2013, 06:32:46 PM
I'm just not getting this:  I'm sorry, I'm still back on this point.  But, suppose I want to measure sensor sharpness.  Why, I don't know, but this thread is about sensor sharpness.  I use a 5D Mark III with a 35 f/1.4L.  I then use a 7D, with a 16-35 f/2.8L II at 22mm, hypothetically.

How is this not apples to oranges?  You switched lenses??  Which is sharper, the FF or the APS-C?  I don't know, because I don't know if it's the lens, or the sensor, or both, or neither.

Neuro's test, to me at least, isolates sensor sharpness only, and leaves no other, or fewer, variables that could influence the test other than pure sensor sharpness.

Nothing personal, I'm just not getting what you are doing.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 08:07:43 PM
I'm just not getting this:  I'm sorry, I'm still back on this point.  But, suppose I want to measure sensor sharpness.  Why, I don't know, but this thread is about sensor sharpness.

Strange. I thought it was about format sharpness, of which the abstract dimensionless notion of sensor sharpness is just one rather insignificant part.

Perhaps if you could explain what you mean by the difference between a sharp sensor as opposed to a sharp camera we could make some progress.

Is a sharp sensor something that makes the sharpest images of newspapers taped to a wall, doing whatever you need to to maximize the sharpness of said newspaper?

If so...who cares? Why would you not be more interested in how sharp the camera system as a whole is when used the way cameras are actually used?

Let's say you rubbed a lamp and got three wishes and used one of them for the sharpest sensor in the world. But the trickster genie gave you a sensor that only produced sharp images when used at a distance of 1" from its subject. What good would that do you?

Unless, of course, all you do is photograph newspapers taped to walls...in which case, I gotta tell you, there are much better ways to make sharp images of a newspaper than by taping it to a wall and photographing it with a camera....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 25, 2013, 08:11:45 PM
I'm just not getting this:  I'm sorry, I'm still back on this point.  But, suppose I want to measure sensor sharpness.  Why, I don't know, but this thread is about sensor sharpness.

Strange. I thought it was about format sharpness, of which the abstract dimensionless notion of sensor sharpness is just one rather insignificant part.

Perhaps if you could explain what you mean by the difference between a sharp sensor as opposed to a sharp camera we could make some progress.

Is a sharp sensor something that makes the sharpest images of newspapers taped to a wall, doing whatever you need to to maximize the sharpness of said newspaper?

If so...who cares? Why would you not be more interested in how sharp the camera system as a whole is when used the way cameras are actually used?

Let's say you rubbed a lamp and got three wishes and used one of them for the sharpest sensor in the world. But the trickster genie gave you a sensor that only produced sharp images when used at a distance of 1" from its subject. What good would that do you?

Unless, of course, all you do is photograph newspapers taped to walls...in which case, I gotta tell you, there are much better ways to make sharp images of a newspaper than by taping it to a wall and photographing it with a camera....

b&

Right, so why would you change lenses?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 08:25:02 PM
Right, so why would you change lenses?

Let's pretend you're a student in a photography course, and the teacher gives you an assignment. "Here're three cameras, and I want you to use each of them make an attractive passport-style headshot portrait of our model for her acting portfolio. All three photos should have the model's whole face in focus but her hair should be a bit (but not excessively) on the dreamily soft side. Pick any lenses in the school's inventory you want for the assignment."

The three cameras are a 4/3 MILC, a Hasselblad loaded with 120 film, and a beat-up old Graflex Crown Graphic 4x5.

Which lenses do you pick for each camera, what apertures do you shoot them at, what distance do you shoot them from, and why?

When you can answer that, you will understand why I structured my experiment the way I did.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TheSuede on January 25, 2013, 09:04:16 PM
Right, so why would you change lenses?

Because... If I shot the same lens on an APS camera as I would have used if I was holding one of my FF cameras, images would look like this:

(https://lh5.googleusercontent.com/-Ewyu-UL0LSo/UQM4wQ1YrTI/AAAAAAAAE_g/5TLemQu-DEA/s800/_DSC1051.jpg)

(https://lh4.googleusercontent.com/-Z343qCFDXjE/UQM4wJq8VkI/AAAAAAAAE_c/GQEy31vQOds/s800/_DSC4955.jpg)

(https://lh3.googleusercontent.com/-84X3gpQqBDs/UQM4wnS5dQI/AAAAAAAAE_k/KA07d2OxwHI/s800/_DSC5258.jpg)

-And that would be kind of embarrassing.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 25, 2013, 09:06:20 PM
Right, so why would you change lenses?

Because... If I shot the same lens as I would have used if I was holding one of my FF cameras, images would look like this:

Looks good to me -- shrinkwrap them and slap on a price sticker!

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 25, 2013, 11:33:47 PM
Right, so why would you change lenses?

Because... If I shot the same lens on an APS camera as I would have used if I was holding one of my FF cameras, images would look like this:

(https://lh5.googleusercontent.com/-Ewyu-UL0LSo/UQM4wQ1YrTI/AAAAAAAAE_g/5TLemQu-DEA/s800/_DSC1051.jpg)

(https://lh4.googleusercontent.com/-Z343qCFDXjE/UQM4wJq8VkI/AAAAAAAAE_c/GQEy31vQOds/s800/_DSC4955.jpg)

(https://lh3.googleusercontent.com/-84X3gpQqBDs/UQM4wnS5dQI/AAAAAAAAE_k/KA07d2OxwHI/s800/_DSC5258.jpg)

-And that would be kind of embarrassing.

But I thought the test was one of format sharpness, not properly composed photography.  Again, maybe I'm missing the point of the thread, but it seems so silly, so I'll move on.  Thank you for your replies.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Passport on January 26, 2013, 01:09:31 AM
If the object is to compare sensors of equal number of pixels for sharpness and nothing else, why not provide a colimated light soure to adjacent pixels in a checkerboard pattern such that neighbors get alternately 0 photons and photons beyond saturation.  Take the digital data and blow it up any number of times, 5, 10, 1000, or a billion.  Sensor size is immaterial if you remove all the optical variables.  The digital data will be identical regardless of sensor size.  Prints made from either sensor will be identical.

Pick a limited number of variables and you could have the alleged photocopier.

Pick a realistic number of variables and we are beginning to talk photography.  Pick your poison and make your pitch.

Generally, system resolution is calculated by taking the reciprocal of the sum of the reciprocals of the elements of the system.  For simplicity, if you have film or a sensor that will resolve 100 line pairs per millimitre and a lens that will resolve 100 line pairs per millimitre, the best that can be hoped for is (1/100+1/100)^-1.  That is 50 line pairs per millimitre.  In reality you need to add contrast factors, paper resolution, printer resolution.  Back in the day I added enlarger lens resolution to the calculations.

Take a lens that has infinite resolution and a sensor that has 100 lp/mm and you get 100 out of the system.  Take a sensor with 100 billion pixels and feed it an image with 100 lp/mm lens and you get a resolution approaching 100 lp/mm out.  A larger sensor has more millimitres than the small one hence a higher total number of line pairs.

Numerous factors including optical diffraction limits, lens abberations and sensor noise give larger sensor of comparable technology with identical pixel count and proportionately larger pixels an advantage in resolving detail.  Mechanical accuracy of mount alignment and distance to sensor proportionately favours the larger sensor as well.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: kanonpokajanen on January 26, 2013, 01:45:52 AM
I believe Passport beat me to it but here is a simple, albeit imperfect, test ;)

-Take two cameras with identical processors, flange distance, pixel count, and lens, but with camera A having full-frame, and camera B, an APS-C sized sensor.

-Place a high-res blowup of the first page of War and Peace on the wall, and take a photo with each camera, at the same shutter speed and aperture, from the same distance away (at an optimal exposure, of course), so that the page fills the frame of camera A.

-Make a 200x enlargement [print] of each photo [file].(camera A = 360mmX240mm, and camera B = 222mmX148mm)

Take a pair of scissors, and cut down the camera A print so that it matches the framing (size) of the camera B print.

Compare prints for sharpness.

Finish reading War and Peace.



Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: serendipidy on January 26, 2013, 03:07:46 AM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 09:04:12 AM
But I thought the test was one of format sharpness, not properly composed photography.  Again, maybe I'm missing the point of the thread, but it seems so silly, so I'll move on.  Thank you for your replies.

Let's say you have two very similar cars with two significantly different powerplants. Both engines have the same horsepower and torque at maximum RPM, but one engine (electric) has constant torque over the entire speed range and therefore a simple transmission while the other (gasoline) only produces maximum torque at maximum RPM and therefore has a geared transmission. Everything else -- chassis, curb weight, suspension, range with full fuel, etc. -- is the same.

The photocopyists in this thread will say that there's no difference between the two engines because they both output the same theoretical maximum capability.

The photographers in this thread will say that the car with constant torque will eat the other car's lunch because it'll handily win the race.

To further confuse matters, the same name applies to both the car model and its engine.

(I'm not a car nut so apologies if I got the technical details of the analogy worng. But, hey -- everybody loves car analogies, right?)

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 26, 2013, 09:39:46 AM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P

It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 10:18:48 AM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P

It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.

That's certainly true, but it's only a small part of the story.

The main reason has to do with simple geometry.

All cameras have lenses that project an image onto the sensor (/ film). And the dimensions of said sensor are fixed for said camera.

With rare exception, those sensors are much smaller than the final display size of the image that gets recorded.

Therefore, all photographic images get enlarged from their capture size on the sensor to their display size on the print or monitor.

The bigger the sensor, the less enlargement necessary.

It is unlikely you'll encounter a sharper photograph than a contact print made from an 8x10 view camera -- assuming, of course, all the usual caveats about lens quality and film chemistry and technique and the rest. It's certainly possible to screw it up, but, when done right, that's about as good as it gets. (One of those oversized Polaroids might be better...I've never seen one, so I don't know.)

In contrast to the lack of enlargement in an 8x10 print made from a view camera, an 8x10 print made from a 135 camera ("full frame") must be enlarged 7 times from the original image projected onto and captured by the sensor. Unless that original capture is at least 7 times sharper than the original capture with the view camera -- say, 7 times the linear pixel resolution of the sensor, or a lens that resolves 7 times as many line pairs, or whatever -- then the 8x10 print from the view camera is going to be sharper than the 8x10 print from the 135 camera.

Imagine you've got two square sensors. One is 1" x 1", the other 10" x 10". Both are divided into 1000 x 1000 pixel grids for a grand total of one megapickle on each sensor. Now, make a 10" x 10" print from each. The larger format is doing no magnification or interpolation, but the smaller format must enlarge each of its pixels 10 times to make the final print. Unless those original pixels on the smaller format are ten times better than the original pixels on the larger format, the larger format is going to win.

But...if you could make pixels ten times smaller and ten times better for the smaller format, why not also for the larger format? Take a hundred of the smaller sensors and line them all up in a 10" x 10" grid, and this new composite sensor is going to absolutely smoke the other two by an insane margin.

The difference between APS-C and 135 isn't the 7 times of the difference between 135 and 8x10. It's only a factor of 1.6. It's not all that hard to come up with something 1.6 times better in the smaller format. Hell, just using a tripod can make that much difference, as can a decade of technological advances. It's because the difference between APS-C and 135 is so minor that we're having this discussion, that there's even a question in the first place. But that difference is there, and it will always be there, even when the margins get blurry.

But, as a rough rule of thumb, if you're happy with a 15" x 22" print from an APS-C camera, you'll be equally happy with a 24" x 36" print from a 135 camera with comparable specs. Both represent a 25x enlargement from the original sensor capture. But, if you're happy with a 15" x 22" print from an APS-C camera, you're probably also going to find a 24" x 36" print from that same APS-C camera quite acceptable, because it's not going to be a whole lot softer than the print from the 135 camera. You'll probably be able to tell the difference if you look closely enough...but, again, if the image made from the APS-C was shot with good technique and the image made from the 135 camera wasn't, the APS-C shot will easily win.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 26, 2013, 10:32:26 AM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P

It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.

In the '80's a got an adapter to enable my Pentax 6x7 lenses fit 35mm cameras.

I was quite disappointed in the results on 35mm - they were definitely not as sharp or contrasty as the 35mm lenses.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 26, 2013, 10:44:49 AM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P

It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.

In the '80's a got an adapter to enable my Pentax 6x7 lenses fit 35mm cameras.

I was quite disappointed in the results on 35mm - they were definitely not as sharp or contrasty as the 35mm lenses.

And they made cool lenses like this back in that era.  8) 240mm F/1.2
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 26, 2013, 11:53:58 AM
It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.
Not entirely accurate.

It would be equally sensible to claim that a small sensor will be less critical of the flaws in the lens infront of it. Lenses tend to perform their worst in corners, and if the sensor does not record anything in corners, you avoid such problems.

-h



What I have been saying for a while...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 12:11:47 PM
Trumpet Power wrote: Imagine you've got two square sensors. One is 1" x 1", the other 10" x 10". Both are divided into 1000 x 1000 pixel grids for a grand total of one megapickle on each sensor. Now, make a 10" x 10" print from each. The larger format is doing no magnification or interpolation, but the smaller format must enlarge each of its pixels 10 times to make the final print. Unless those original pixels on the smaller format are ten times better than the original pixels on the larger format, the larger format is going to win.

enlarger each of the pixels ? how do you do that? enlarge a charge?
it is the  signal  ratio from each pixel  who are  important  and if they are equal then it is then a pure  optically question

Let me give a slightly modified example.

Imagine you create a digital file from each sensor and then view the images on a 100ppi monitor.

In both cases you're pixel peeping, viewing a 10" x 10" 100ppi image on your monitor.

In the case of the large format sensor, the pixels you're looking at are the exact same size as the pixels on the sensor. You're essentially looking at the digital equivalent of a contact print.

In the case of the small format sensor, the pixels you're looking at are ten times the size of the pixels on the sensor. Each pixel has been enlarged ten times. You're essentially looking at the digital equivalent of an 8x10 print made from APS-C.

Does that help?

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: kanonpokajanen on January 26, 2013, 01:53:02 PM
No.  Your example only works at the low end of the spectrum.(where enlargement of smaller sensor image/pixels is necessary)

If both sensors have the same pixel count and that number is larger than the resolution of the monitor you a viewing them on, the sharpness will be identical.(assuming the captured images are identical)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 02:52:10 PM
No.  Your example only works at the low end of the spectrum.(where enlargement of smaller sensor image/pixels is necessary)

If both sensors have the same pixel count and that number is larger than the resolution of the monitor you a viewing them on, the sharpness will be identical.(assuming the captured images are identical)

Maybe somebody could help me explain why everybody here seems to think that a pixel is an absolute unit of length as opposed to the dimensionless number it actually is.

When you take a photo with APS-C and make a 24" x 36" print, you're taking an image projected onto a 14.8mm x 22.2mm surface and then enlarging it 41x. When you take a photo with 135 and make a 24" x 36" print, you're taking an image projected onto a 24mm x 36mm surface and then enlarging it 25.4x.

The resolution of the original 14.8mm x 22.2mm image compared with the resolution of the original 24mm x 36mm image is nowhere near as important as the fact that you're blowing up the one half again as much as you're blowing up the other.

And that's true regardless of the absolute amount of magnification, whether you're pixel peeping, or anything else.

Your objection would apply if a pixel were an absolute unit of measurement, if every pixel were always the exact same size. But your objection is incoherent given the fact that a pixel can be any size from a micron to a mile or more or less.

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 26, 2013, 03:21:02 PM
@ TrumpetPower, you are certainly tenacious if nothing else.

It seems to me that you have a number of spades which you are using to dig this hole you're  in  :)

One of them is this business of enlarging pixels. From my understanding of your posts it seems to me that you think the pixels you see on your screen are the same ones on your sensor. You talk about the large theoretical sensor being printed as is, but the small one being interpolated up- but any electrical info from the pixels on the camera sensor has to be "interpolated" in order to display it on your screen as a ( completely different ) type of "pixel". The ambiguous term "pixel" is probably responsible for this misunderstanding.

The second spade is when you compare enlarging film to enlarging digital, the enlargement process is totally unrelated. If you're going to keep fighting your corner on this one I wouldn't mention film anymore.

Also the actual size of the image projected onto the sensor is creating another confusion here. Yes it's true to say the recorded image as it falls on the sensor is larger on a larger sensor, but the ability to record it accurately comes down to lenses and pixel efficiency, so having a ( slightly ) larger light image on the sensor does not necessarily mean it has been recorded more accurately.

Clear as mud  ;)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 04:13:18 PM
From my understanding of your posts it seems to me that you think the pixels you see on your screen are the same ones on your sensor.

Eh, you might be the one with a bit of confusion as to what a pixel is.

When you're looking at a 100% crop of an image, the pixels on your monitor are a (close to) perfect representation of the pixels on the sensor, just magnified a Brazilian times. There are caveats, of course, insofar as there are different color gamuts and luminance mapping and what-not, but those have no practical bearing on the discussion.

Quote
Also the actual size of the image projected onto the sensor is creating another confusion here. Yes it's true to say the recorded image as it falls on the sensor is larger on a larger sensor, but the ability to record it accurately comes down to lenses and pixel efficiency, so having a ( slightly ) larger light image on the sensor does not necessarily mean it has been recorded more accurately.

As with so many others, you're significantly overstating the importance of the megapickles.

Can a smaller format system produce sharper images than a larger format system? Yes, but not by merely matching the (in the case of digital) total pixel count of the larger format. You need at least the same number of megapickles to make up for the quantization advantage of the larger format, but you then need even more (resolution, optics quality, whatever) to make up for the surface area advantage of the larger format.

And this is where film is such a useful example to bring into the mix. Let's say you developed some fantastic new film that was so much better than the film currently being used in 120 film that it made a 135 camera produce images as good as those from 645. Great news! But the very next thing that's going to happen is that said film is going to get packaged into a 120 roll...and now the 645 images are going to be just as much better. Indeed, the 645 images with the new film are going to be as good as 4x5 images with the old film...but, again, the large format shooters are going to be all over the new film, and the 4x5 images are going to be as good as 8x10, and the 8x10 images are going to be better than original reality.

That's the exact same thing we see with digital formats, except that the expense of scaling up film formats is much gentler than the expense of scaling up new digital formats.

So please, by all means. Support enhanced image quality in smaller formats. But what makes you think those same enhancements aren't on their way to the larger formats as well?

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Sporgon on January 26, 2013, 04:55:32 PM
Ah well........

Incidentally I'm a dyed in the wool FF user.

At least we both agree the 40mm pancake is a little gem  ;)
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 05:09:19 PM
Honestly, I can not understand  what you writing Trumpet Power, you use long sentence, many words.
It is the charge from each sensor small or big  who are importand, there is no enlarging regarding a sensors charge , as long it is the same  charge from a big or small sensor it is a optical question
AND if you do not understand this is it time for you to study the subject.


and cheers cheers and cheers
it is a question about  Physics

You don't like my English, so here's some math. I've even formatted it all so you can copy / paste into Google and it'll crunch the numbers for you.

To make a 24" x 36" print:

APS-C format = sqrt(24 in * 24 in + 36 in * 36 in) / sqrt(14.8 mm * 14.8 mm + 22.2 mm * 22.2 mm) = 41.19x enlargement

135 format = sqrt(24 in * 24 in + 36 in * 36 in) / sqrt(24 mm * 24 mm + 36 mm * 36 mm) = 25.4x enlargement

41.19 / 25.4 = 1.62 times as much enlargement for APS-C than for 135. (And, yes, that number should be very familiar.)

That's it. That the whole explanation for the superiority of 135 format over APS-C format -- or for any other large format over any other small format.

If you still don't understand, start playing around with some paper, a ruler, scissors, and a magnifying glass until you've got it figured out.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 26, 2013, 05:38:01 PM
I created a few webpages about this topic here:

http://plamen.emilstefanov.net/index.htm (http://plamen.emilstefanov.net/index.htm)

The answer is YES in principle but this also depends on the other factors.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AprilForever on January 26, 2013, 05:51:28 PM
From my understanding of your posts it seems to me that you think the pixels you see on your screen are the same ones on your sensor.

Eh, you might be the one with a bit of confusion as to what a pixel is.

When you're looking at a 100% crop of an image, the pixels on your monitor are a (close to) perfect representation of the pixels on the sensor, just magnified a Brazilian times. There are caveats, of course, insofar as there are different color gamuts and luminance mapping and what-not, but those have no practical bearing on the discussion.

Quote
Also the actual size of the image projected onto the sensor is creating another confusion here. Yes it's true to say the recorded image as it falls on the sensor is larger on a larger sensor, but the ability to record it accurately comes down to lenses and pixel efficiency, so having a ( slightly ) larger light image on the sensor does not necessarily mean it has been recorded more accurately.

As with so many others, you're significantly overstating the importance of the megapickles.

Can a smaller format system produce sharper images than a larger format system? Yes, but not by merely matching the (in the case of digital) total pixel count of the larger format. You need at least the same number of megapickles to make up for the quantization advantage of the larger format, but you then need even more (resolution, optics quality, whatever) to make up for the surface area advantage of the larger format.

And this is where film is such a useful example to bring into the mix. Let's say you developed some fantastic new film that was so much better than the film currently being used in 120 film that it made a 135 camera produce images as good as those from 645. Great news! But the very next thing that's going to happen is that said film is going to get packaged into a 120 roll...and now the 645 images are going to be just as much better. Indeed, the 645 images with the new film are going to be as good as 4x5 images with the old film...but, again, the large format shooters are going to be all over the new film, and the 4x5 images are going to be as good as 8x10, and the 8x10 images are going to be better than original reality.

That's the exact same thing we see with digital formats, except that the expense of scaling up film formats is much gentler than the expense of scaling up new digital formats.

So please, by all means. Support enhanced image quality in smaller formats. But what makes you think those same enhancements aren't on their way to the larger formats as well?

Cheers,

b&

To quote a great luminary: "Don't underestimate the power of the megapickle." (Darth Vader, when discussing the 7D vs the 1D4 with the Emperor)

A few extra megapixels goes a long long way...
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 06:07:45 PM
what is it you do not understand Trumpet Power?
se earlier answers regarding pixels and charge, s/n, there is no enlargement regarding a charge, IT IS a optical question  if the charge is equal from a smaller or bigger sensor and with the same resolution

it requires more from a lens to reproduce  the smaller sensor's pixel density

and 2 examples , it requires 1,6 more of a lens for APS sensor compared to the same  same resolution  from a 24x36mm sensor , and the same if you compare  a 24x36 mm sensor with a medium format sensor, it requires more from the lens to reproduce a 24 x36mm sensors 40MP than it does from a medium format sensors and 40MP

and read now back and look at what you have been writing

Mikael, if you need a lens that's 1.6 times sharper to get the same image out of APS-C than out of 135, then it should be self-evident that, with lenses of equal sharpness, the 135 format is 16 times sharper than APS-C.

In other words, larger formats are sharper. Sharper lenses are sharper, too, but you can combine a sharp lens with a large format to get an even sharper image than you can with a sharp lens and a small format.

That's what "all else being equal" means. If the lenses are of equal sharpness, if the sensors have the same S/N ratio and other technological characteristics, if everything else is equal, the camera with the larger format will be sharper.

This is what I've been writing from the beginning. If you still don't get it, then at best, your English isn't good enough for you to participate in this discussion.

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 06:16:10 PM
I created a few webpages about this topic here:

http://plamen.emilstefanov.net/index.htm (http://plamen.emilstefanov.net/index.htm)

The answer is YES in principle but this also depends on the other factors.

Plamen's site has it all perfectly correct, with all sorts of thorough and clear explanations and examples. And a really good shot of some very impressive traditional African tribal garb.

Most thoroughly recommended.

...and I'll recommend it even more thoroughly once you get it out of the '90s-style under construction look....

Cheers,

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: serendipidy on January 26, 2013, 07:18:58 PM
Is Full Frame sharper than APS-C?

After Way Too Much Time spent reading this thread, I still don't know :P

It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.

Thank you for simplifying this. I vote for FF.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 26, 2013, 07:41:42 PM
I created a few webpages about this topic here:

http://plamen.emilstefanov.net/index.htm (http://plamen.emilstefanov.net/index.htm)

The answer is YES in principle but this also depends on the other factors.
...and I'll recommend it even more thoroughly once you get it out of the '90s-style under construction look....

LOL! :) You are pretty close! This is the default look of FrontPage 2003, only 10 years old.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: RLPhoto on January 26, 2013, 07:56:40 PM
It's quite simple. A larger sensor/film will be less critical of the flaws in the lens infront of it. IE: it's make bad lenses not look so bad.
Not entirely accurate.

It would be equally sensible to claim that a small sensor will be less critical of the flaws in the lens infront of it. Lenses tend to perform their worst in corners, and if the sensor does not record anything in corners, you avoid such problems.

-h



What I have been saying for a while...

Only someone who's never shot MF would say this.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: zim on January 26, 2013, 08:24:49 PM
16 pages and counting…..Folks I here Spielberg is interested in the film rights (APS-C format of course) :P
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: TrumpetPower! on January 26, 2013, 08:34:28 PM
I created a few webpages about this topic here:

http://plamen.emilstefanov.net/index.htm (http://plamen.emilstefanov.net/index.htm)

The answer is YES in principle but this also depends on the other factors.
...and I'll recommend it even more thoroughly once you get it out of the '90s-style under construction look....

LOL! :) You are pretty close! This is the default look of FrontPage 2003, only 10 years old.

FrontPage...FrontPage...FrontPage....

Nope, I'm delighted to state, for the record, that I have absolutely no recollection whatsoever of what on Earth you might be referring to.

...and you won't do a damned thing to change that state of affairs, if you know what's good for you....

b&
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 27, 2013, 04:39:43 PM
Despite all the acrimony in this thread, there is some interesting stuff. I would not dispute that that a FF is better than an APS-C with a 1.6xshorter focal length lens so that the whole picture area has the same field of view. I am interested in photography at super telephoto distance where crop factor is thought to be important. So, I decided to do a rough and ready test of FF vs APS-C doing my favourite hobby, taking photos of birds with a 300mm f/2.8 II +2xTC III. Accordingly, I took my ancient 7D and my new 5DIII and did the Old Grey Heron Test (parodying http://en.wikipedia.org/wiki/The_Old_Grey_Whistle_Test (http://en.wikipedia.org/wiki/The_Old_Grey_Whistle_Test)). The heron did his bit, stayed in one place long enough so I could switch bodies. The 7D was at iso 400 and the 5DIII at 640. Consistent with my other recent experience, the IQ of the 5DIII makes up for the crop factor loss of 1.5 fold as the two centre crops were quite similar. The 7D was noisier, as expected. I usually use it at iso 320 or less. At great length extremes, the 7D does have an advantage but otherwise the FF is just as good for bird photography with the same lenses, and the closer you get to the target, the better it should be. It will be interesting to see when the 7D II comes out with more modern technology if it can overtake the 5DIII in the telephoto range,
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: neuroanatomist on January 27, 2013, 06:41:54 PM
Consistent with my other recent experience, the IQ of the 5DIII makes up for the crop factor loss of 1.5 fold as the two centre crops were quite similar. The 7D was noisier, as expected. I usually use it at iso 320 or less. At great length extremes, the 7D does have an advantage but otherwise the FF is just as good for bird photography with the same lenses, and the closer you get to the target, the better it should be. It will be interesting to see when the 7D II comes out with more modern technology if it can overtake the 5DIII in the telephoto range,

^^ This is why I don't use my 7D anymore...  Add to that the case of the 600/4, where the FF 1D X will autofocus with a 2x TC for 1200mm focal length, compared to the 7D which needs f/5.6 for phase AF and therefore is limited to the 1.4x TC and a FF-equivalent of 1344mm - an effective 'crop factor benefit' of only 1.12x. 
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: bdunbar79 on January 27, 2013, 07:18:49 PM
From my understanding of your posts it seems to me that you think the pixels you see on your screen are the same ones on your sensor.

Eh, you might be the one with a bit of confusion as to what a pixel is.

When you're looking at a 100% crop of an image, the pixels on your monitor are a (close to) perfect representation of the pixels on the sensor, just magnified a Brazilian times. There are caveats, of course, insofar as there are different color gamuts and luminance mapping and what-not, but those have no practical bearing on the discussion.

Quote
Also the actual size of the image projected onto the sensor is creating another confusion here. Yes it's true to say the recorded image as it falls on the sensor is larger on a larger sensor, but the ability to record it accurately comes down to lenses and pixel efficiency, so having a ( slightly ) larger light image on the sensor does not necessarily mean it has been recorded more accurately.

As with so many others, you're significantly overstating the importance of the megapickles.

Can a smaller format system produce sharper images than a larger format system? Yes, but not by merely matching the (in the case of digital) total pixel count of the larger format. You need at least the same number of megapickles to make up for the quantization advantage of the larger format, but you then need even more (resolution, optics quality, whatever) to make up for the surface area advantage of the larger format.

And this is where film is such a useful example to bring into the mix. Let's say you developed some fantastic new film that was so much better than the film currently being used in 120 film that it made a 135 camera produce images as good as those from 645. Great news! But the very next thing that's going to happen is that said film is going to get packaged into a 120 roll...and now the 645 images are going to be just as much better. Indeed, the 645 images with the new film are going to be as good as 4x5 images with the old film...but, again, the large format shooters are going to be all over the new film, and the 4x5 images are going to be as good as 8x10, and the 8x10 images are going to be better than original reality.

That's the exact same thing we see with digital formats, except that the expense of scaling up film formats is much gentler than the expense of scaling up new digital formats.

So please, by all means. Support enhanced image quality in smaller formats. But what makes you think those same enhancements aren't on their way to the larger formats as well?

Cheers,

b&

To quote a great luminary: "Don't underestimate the power of the megapickle." (Darth Vader, when discussing the 7D vs the 1D4 with the Emperor)

A few extra megapixels goes a long long way...

Hmmm, I'm lost.  The 1D4 has much better IQ than the 7D.  Or was that a joke?  If so, good one!
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: steven kessel on January 27, 2013, 07:48:47 PM
That Gray Heron test confirms my own experience.  I own both a 7D and a 5D Mark iii.  I find that the Mark iii produces consistently sharper photos, in part because of its superior autofocus (much superior!) and also because of its noise handling ability.  I routinely shoot at ISO 320 with my 7D and at 640 with the 5D Mark iii.  The vastly superior technology of the Mark iii more than compensates for the need to crop.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: kanonpokajanen on January 29, 2013, 12:10:19 AM
Thank you, Plamen, for the excellent article and graph.

(of the first graph) Does it in fact say that a 7D @ f6 out resolves a 5D2 @ f20?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 29, 2013, 01:09:49 AM
Thank you, Plamen, for the excellent article and graph.
Thank you.
Quote
(of the first graph) Does it in fact say that a 7D @ f6 out resolves a 5D2 @ f20?
It should. Diffraction will soften the image a lot at f/20. See also this (http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=106&Camera=453&Sample=0&FLI=0&API=5&LensComp=115&CameraComp=736&SampleComp=0&FLIComp=0&APIComp=4).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 29, 2013, 05:41:28 PM
Really great article, Plamen. It proves all the sane stuff in this thread: FF beats out crop when each sensor covers the same field with different focal length lenses etc but crop and FF are quite similar when they have the same pixel density and are with the same high quality lens.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 29, 2013, 10:33:02 PM
Please label the axes of the graph.  I can guess at some but not all.  What is the y-axis (S/N?)? What are the numerical values? What are the units - Is it Lin or log? What is the colour key?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: kanonpokajanen on January 29, 2013, 11:08:53 PM
Plamen, would it be possible to make a graph that not only accounts for the 8% MP differential, but also adjusts for the aperture to sensor size ratio?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 30, 2013, 12:03:53 AM
Plamen, would it be possible to make a graph that not only accounts for the 8% MP differential, but also adjusts for the aperture to sensor size ratio?
I am not sure what that means. The graphs that I have there are in equivalent f-stops, which means the same ratio (same "pupil" a.k.a "physical aperture" size). For example 50/2 vs 80/3.2. Since the FL is proportional to the sensor size, you can think that with equivalent shots, the ratio of linear sensor size vs. the f-stop number (but not physical aperture!) stays the same. In the example above, So FL/(f-stop) is the same, (sensor width)/(f-stop) remains the same but (sensor width)/(physical aperture) is not.
Or maybe you mean an interactive graph of some sort? Icannot do such things.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Don Haines on January 30, 2013, 10:09:53 PM
It will be interesting to see when the 7D II comes out with more modern technology if it can overtake the 5DIII in the telephoto range,

I am also curious as to how a newer 7Dii would compare... I'd bet it would be VERY close...

What you have shown us is that BOTH cameras take nice pictures.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: AlanF on January 30, 2013, 11:07:00 PM
Agreed about both taking very good pictures.  The 7D under the right conditions performs just as well as its expensive brother.  On the other hand, much of the advantage of crop in giving extra reach is illusory. I did some iso12233 chart tests at 100 iso with the 100-400mm L on both bodies as it is a very popular but not very sharp lens - its defects according to Plamen's analysis should show up more on the crop.  At closer distances where the closely spaced lines on the chart are easily resolved, the 5D III gave clearer, more contrasty images. At long distances where the lines were at the limits of resolution, they were marginally better resolved by the 7D but IQ was much poorer from poorer contrast and so again the resultant overall image was not better.

The good news for the bird photography 7D owner is that you have camera that can equal the best (at lower iso).
The good news for the bird photography 5D III or 1DX owner is that you are not really disadvantaged by not having the crop factor (but both owners probably don't need me to tell you that).
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: applecider on January 30, 2013, 11:37:00 PM
Put me down in the heron test in the camp of "full framed cropped 5d3 equals or exceeds 7d for bird photography".  My test was similar to the herons except I used kingfishers in extreme range.  The 5d3 images yielded better detail when cropped to equal framing.  My settings for birds in flight are usually shutter 1250-1600,  f 7.1 to 10 and ISo on automatic.  With the 7d Letting the iso go above 320 in autoiso  has its own issues. 

So for me a ff has more sharpness than crop given the same lens and distance to target.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 30, 2013, 11:50:23 PM
Once Canon releases a high mp FF body, there would be mo much need for crop cameras in term of IQ, but croppers could achieve higher fps for less $$ for those who need them.

I think that Canon should implement a crop mode in their future FF bodies to lower the size of the RAW files (but no need to take EF-S lenses), and keep the sRAW and mRAW options for those who do not want large (non cropped) RAWs. The Nikon compressed RAW format is another option.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Plamen on January 31, 2013, 07:56:02 AM
It means that the sensor in D800  at APS mode = 15,3Mp  has better pixels  signal =they have a greater efficiency than the 7D.

If you are talking about Quantum Efficiency - it depends on the sensor technology, not on the number of the pixels.  In my analysis, I am not taking the noise factor into account. Then, if you crop the D800 to APC size, you are just getting a cropped sensor, something like the 50D but with 1.5 crop factor.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Woody on January 31, 2013, 08:53:13 AM
It means that the sensor in D800  at APS mode = 15,3Mp  has better pixels  signal =they have a greater efficiency than the 7D.

This thread is about resolution, not your all-time-favorite topic on dynamic range and SNR.
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: chauncey on January 31, 2013, 11:37:01 AM
I've read bits and pieces of this thread and I read a little of the math and whatnot, not much that I've understood, but what about the crucial question...print?

You have a small subject 50 yards away (you can't get closer) and a 300mm 2.8 lens attatched to that 7D/5dMkII manually prefocused. 
Now, that small subject will not fill the frame of either camera...you must crop to create an equal field of view and make a 30x30" print.

Which of those cameras is going to cough out the better print?
Title: Re: Is Full Frame sharper than APS-C? My answer here
Post by: Woody on January 31, 2013, 11:54:50 AM
Have I said anything else? from the crop 1,5 =15.3 Mp from the Nikon D800 compare to  Canon 7d the pixels in the Nikon has higher QE compare to 7d APS

Repeat: this thread is about resolution, not your all-time-favorite topic on dynamic range and SNR.