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Messages - dtaylor

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226
EOS Bodies / Re: 7DII and D400 Specs
« on: February 27, 2013, 12:06:49 AM »
If you have an aperture so small that both a high MP body and a low MP body have diffraction, the high MP body will have no advantage. It doesn't matter how finely the sensor can resolve the blur projected by the lens, its still just blur.

Once again, resolution does not work like this. First, diffraction is not a hard limit. Second, even at extreme apertures where diffraction approximates a hard limit, a higher resolution sensor will still yield superior results. Why? Because the resolution of a system is not the weakest link in the chain. It is computed from a formula using all the links and is always less than the weakest one. Increasing any link results in a higher final resolution, but the final resolution is always less than the weakest component.

Practically speaking the increase may not matter outside of a lab. And for 18 vs. 24 MP I'm guessing it won't matter much outside of a lab test even at f/2.8. But putting a higher resolution component in the chain will never result in worse performance.

I hate the term DLA because it's inaccurate and it conveys the idea of a "hard limit" that goes down as the sensor resolution goes up. It is not at all consistent with the science of optics. And it plays off another issue in general conversation: the portrayal of resolution as a single number. It's not a single number. It's an MTF curve. Your comment "it's sill just blur" illustrates the problem. The 7D is "diffraction limited" at f/6.9. The way you describe this, f/8 produces "blur." The reality is that detail with X contrast at f/6.9 has some value <X contrast at f/8, and can be restored to X contrast with sharpening. I can make f/6.9, f/8, and f/11 24" prints all day long and you won't be able to tell me which is which.

At some point detail is truly lost, i.e. contrast of 0%. But the point is not immediately past the DLA.

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While a 24MP sensor with DLA setting in at f6.0 will allow for some lenses to shine at larger apertures, where will this marketing machine stop? If the next round of crop cameras hit 40mp, and then after that 60, will you still be arguing for it to carry on?

I've seen convincing arguments for 100-200 MP FF sensors, assuming technology allows you to hold the line on noise/DR. Why? Because of another point that's not reflected in simple DLA numbers tossed around on the web: the impact of diffraction is different for different wavelengths of light. And if your sensor design + RAW software takes this into consideration, it can maximize the detail recovered. We will eventually see that point in digital camera design.

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There comes a point where making EF-S glass good enough to resolve such detail at the large apertures needed to avoid diffraction becomes unaffordable. We're already at the point where the 17-40L and 24-105L cost less than their EF-S counterparts.

Which counterparts are you thinking of?

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But for those than want the extra MP so they can resolve more detail, in all but very select circumstances and with all but the very best glass, they'll be very dissapointed.

I'll agree that 18 vs. 24 MP is not a very big deal and is driven by marketing. But sensor resolution is not limited by diffraction in the way you think it is. And we will see even higher resolutions in the future. If a jump could be made today to 35 or 40 MP while holding the line on noise/DR, it would produce observably better prints.

227
EOS Bodies / Re: 7DII and D400 Specs
« on: February 26, 2013, 03:49:27 AM »
APS-H is a nice middle ground; better IQ than 1.6, better reach than FF.

We're at the point of diminishing returns where it really doesn't matter with FF vs. 1.6x. There's hardly a reach gain today with 1.6x. It's there, but you pretty much have to crop even further and then print 24" or larger. With 1.3x in the newest generation of sensors you would never see the gain vs. FF.

Likewise, there's hardly an IQ gain with FF except at high ISO. So the IQ difference between 1.3x and 1.6x, with the sensor tech the 7D2 will have, would be a scientific footnote, not a human observable quantity.

We're long past the days of the 5D vs. the 20D where IQ and reach differences were immediately obvious. 1.3x loses compatibility with numerous lenses and increases costs for no real advantage. It's not coming back. APS-C gives you lower cost bodies and, in some cases, lower cost glass. FF gives you more high ISO room. That's about it.

228
EOS Bodies / Re: 7DII and D400 Specs
« on: February 26, 2013, 03:42:06 AM »
Ps - I really hope Canon resist the temptation to take their 1.6x crop sensor up to 24mp. It'll suffer from softness due to diffraction from f6.0 onwards - mount an f5.6 lens on there and you've got little in the way of options. Even the legendary 300/2.8 II with a 2x TC III will underperform, and leave you with just one aperture option if you want to attempt to utilise all of those megapixels.

Resolution doesn't work like this. In a format, a 24 MP sensor will always out perform an 18 MP sensor whatever aperture you choose. Now even under the best conditions it won't amount to much and may not be immediately obvious in large prints. But it will always be better by some amount. Diffraction is not a hard limit and is not a reason to cap APS-C sensor resolution or to limit your use of apertures.

The current 7D is "diffraction limited" at f/6.9. I regularly use f/8 and f/11, and after post processing even f/16 is fine. More to the point, the 7D is never "worse" than the 10D, 20D, 40D, etc., not even at f/22 or f/32.

High ISO is another non-reason to cap resolution. Noise for an image is determined by technology and total surface area, not pixel size. At least not until you get into the extremely small pixels on some P&S bodies.

The only possible reason to hold back on increasing the resolution is DR. Pixel size is a factor for DR. But if technology eclipses this, my guess is Canon will match the competition. Too many people will see 18 vs. 24 MP as a negative, and Canon's not going to give up that marketing point.

Given the choice I would take 18 MP if it had noticeably higher DR. But that choice may not be what anyone thinks it is, i.e. the DR gain may be less then the resolution gain. And I doubt Canon will give us the choice. Their competitors have settled on 24 MP. You can guess what they will do.

229
EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]
« on: February 19, 2013, 01:15:02 PM »
Canon cannot put the same AF-system like the 5D Mark III´s in an 7D Mark II for the mentioned price. So don´t expect it.

Canon could put the 1DX's AF system in every body they've got. The AF components are among the cheapest to manufacture. Like everyone else they use AF specs to segment the market, but the 1DX AF is not actually hundreds of dollars more to manufacture then the Rebel's AF.

Whether or not they will put the 5D3's AF in the 7D2 remains to be seen.

230
EOS Bodies - For Stills / Re: Film EOS Body
« on: February 17, 2013, 07:37:45 PM »
Adding another vote for the EOS3. I actually prefer it over the 1-series film bodies due to size/weight. It's an awesome camera, and the used price right now is a steal.

I was never that crazy about eye controlled focus, though it does work with a reduced set of focus points. (It never works well for me with all 45.) But there are a couple other features I wish were on my 7D. Namely the spot metering mode where you can take multiple readings and the camera will compute the exposure, and the additional metering scale to the right of the viewfinder.

231
EOS Bodies / Re: $1200 7D vs. $1800 5D II?
« on: February 14, 2013, 08:40:41 PM »
5D2 if you regularly shoot and make large prints at ISO 1600 and above. OR if you have certain Canon lenses which really work best on FF (T/S; the fast wide primes like the 35 f/1.4).

7D for everything else.

No matter how many times people insist...just insist...there's a HUGE difference when they pixel peep at 300%, they cannot pick out 16x24 or 20x30 prints at ISO 100-800.

And $600 would make a big dent for lenses, either buying one you need out right, or getting you that much closer to one that's more expensive.

232
EOS Bodies - For Stills / Re: Upgrade from 40D
« on: February 08, 2013, 01:50:47 AM »
1) Used 1D Mark III (yeah, submirror AF blah blah)

Sports and wildlife: excellent
Landscape: OK
Low light: OK

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2) Used 5D Mark II

Sports and wildlife: OK
Landscape: excellent
Low light: excellent

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3) Used 7D

Sports and wildlife: excellent
Landscape: excellent
Low light: OK

Not sure what to say here except that you're probably looking at the 7D or 5D2, and not the 1D3 regardless of the cool factor of having a 1-series camera.

If sports AF/fps are critical, 7D.

If >3200 ISO and/or >11x14 low light prints are critical, 5D2.

Low-mid ISO landscape prints are the same from either after post processing, and you can easily print 16x24 and 20x30.

233
Since we're going to argue this...

DPReview Noise Test Results at ISO 3200:

7D Chroma: 3.3
5D Chroma: 4

7D Luminance Black: 2.7
5D Luminance Black: 3.1

7D Luminance Gray: 3
5D Luminance Gray: 3.4

I don't like the IR comparometer for high ISO because those particular studio tests are not as carefully controlled in regard to lighting. The "Dave Box" test is carefully controlled, and the 7D clearly edges out the 5Dc.

These results apply to any of the 18 MP APS-C bodies.


234
As for its High ISO IQ, Its better than any crop camera canon makes. DXO even confirms this and my own usage agrees also.

Imaging Resource and DPReview confirm the opposite and publish the test photos and all test details for review (reproducibility, something DxO lacks). Should someone believe DxO or their lying eyes?

If we're going to talk experience, my experience, the experience of members at my photo club, and the experience of a friend with a rather successful wedding photography business all concur. Nobody who has ever claimed the opposite has ever been able to provide images to prove it. If you can you'll be the first.

235
Points to consider...

* The shutter counts provided by Canon are estimates of average lifespans. A 1DX might lose a shutter at 10,000 images, while your T1i still clicks at 250,000. That wouldn't be the average, but it certainly can happen and will happen to someone. Don't assume your camera is about to die based on shutter count.

* The 5Dc is definitely better at high ISO then the T1i.

* The T2i / 60D / 7D out perform the 5Dc in all respects, including high ISO / noise. This is a tested, measured, and proven fact for those who want to argue that "FF must always be better!" (See the reproducible tests at DPReview and Imaging Resource.) The differences are small, but in the crop sensor's favor.

* A used 5Dc will have a shutter count equal to or worse than your T1i.

* The 5D2 / 6D has clearly superior noise, sharpness, and fine detail at ISO 1600 and above over the 18 MP APS-C bodies. Add to that superior fine detail at any ISO over the 5Dc. How important this is depends on what you do. 8x10's at 1600 and 3200? It's a non-issue. ISO 6400, 12800, and/or 16x20 high ISO prints? You will definitely appreciate the 5D2 or 6D.

My recommendation:

* If you absolutely need the high ISO performance (i.e. >3200 and/or lots of 16x20 prints at ISO 1600 and above), your budget only allows for a used 5D2.

* If you are leaning towards the 5Dc because you also want a new lens, you should be looking at Canon's 18 MP APS-C bodies. (What crop glass do you have btw?)

* Unless you get one really cheap, it's hard to recommend a 5Dc that will have just as much wear and tear as your Rebel, and fewer features. It is better at high ISO then your Rebel. At the right price it could be a good move with your budget and a lens. But every time I check the 5Dc's they are overpriced because people think FF is "magic" when it's not. At any price I've seen them, the 60D is a far better option.

236
This thread seems surreal.  Unless shooting in the studio under carefully conceived lighting, good post production and printing small, how can so many people say the iq difference between a rebel and a mkiii is similar, not to mention indiscernible?

Because we've taken a wide range of shots under a wide range of lighting conditions, and printed them to large sizes. And at ISO 100-800 the differences just aren't there.

Above 800? Absolutely. Though I would say the 18 MP sensor is good through 3200, the FF sensor shows a greater and greater advantage with each stop past 800. I consider the 5D3 probably the best low light DSLR made. (Haven't tried a 6D.) But if you're not shooting at those ISOs, it just doesn't show an IQ advantage over the many other sensors out there. (Canon's 18 MP APS-C; 5D2 sensor; several Nikon / Sony sensors).

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I don't think that once you shoot the mkiii in the real world, you would ever choose to shoot the rebel.

He just told you he observed the opposite. Should he believe you, or his lying eyes?

Again I'll say that, given the trip, he should keep the 5D3 unless he is short a critical lens and trading the 5D3 for a 7D gets him the lens. It sounds like that's probably not the case, though his kit is weak on the telephoto end. At the bare minimum he's going to need a 1.4x for the 70-200. And I lean towards the comment that even that won't be enough, and a 100-400 will be the bare minimum for wildlife in this scenario.

237
1. A stop better ISO performance is DESTROYED in my book. The 5D3 is atleast 2 stops better.

Most people would not agree with your definition of "destroyed." But exaggerate away if you must.

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2. haha, Thats a joke right? @ 100 ISO my 7D is like Iso 400-800 on my 5D3.

Which is why OP found such a huge difference in his tests at low ISO.

Oh wait...he found none  ::)

238
The 5D3 will destroy the rebels IQ at higher ISOs,

"Destroy" is an exaggeration, but it will certainly be better.

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larger prints, and in sharpness from FF.

At low to mid ISO there won't be an observable difference, as our friend discovered.

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In camera performance, the 5d3 can handle tricky AF situations that would make the rebel sweat. It's also sealed.


Agreed.

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I wouldn't keep the rebel and you'll never need to buy another camera with the 5D3. You'll never outgrow it.

Given his trip, the Rebel makes a fine backup body on a budget.

239
i bought a 5D Mark3 and a 650D at amazon.
now i have 24 days left to decide if i keep the 5D Mark3 or the 650D

what puzzles me is that the image quality is, as far as i can tell, exactly the same.
i bought a epson R3000 printer and when i print the files i can hardly see any difference.

It's hard to express the joy I get out of a post like this ;D

The reason you can hardly see a difference is because contrary to the exaggerated claims of some FF fans, there is hardly a difference at low to mid ISO. Properly processed and printed, a shot from Canon's 18 MP crop sensor in that ISO range will be indistinguishable from a shot from any of Canon's FF sensors. This is true at 13x19, 16x24, 20x30...any size actually.

At high ISO Canon's FF sensors start to show their edge. If you're shooting ISO 1600 or 3200 and making larger prints, you will observe improved IQ with the FF sensor. At 6400 and above the difference will be large. That said, Canon's 18 MP crop sensor makes very good prints through ISO 3200 with a little NR.

As to what you should do: I'm leaning towards the recommendation that you keep the 5D3 because of your trip. That's a once in a lifetime experience and the 5D3's AF, high ISO, and weather sealing will not let you down. I would maybe suggest returning it for a 7D if you need additional lenses for that trip and if you can use the money saved for that purpose. I don't know your budget so I can't make that call.

You mention wanting to buy a 24-70 zoom and a wider prime. What is your longest lens? If you are going to do any wildlife shooting on that trip, I would suggest budgeting for an additional telephoto. Canon's 300 f/4L IS and a 1.4x teleconverter (which could also be used with your 70-200), or a 100-400L.

If you can get the lenses you need and keep the 5D3, I would go that route. If you are going to be without a critical lens for the trip, consider the 7D plus the lens you need. Either way, try to keep the 650D for a backup. If you can't, take something as a backup, a P&S super zoom maybe. Again, it's a once in a lifetime event so make sure you're prepared.

240
Lenses / Re: Which 50mm (with AF) is best from f/1.4 - f/2.0?
« on: January 29, 2013, 11:13:44 AM »
Then there's the Sigma 50/1.4. I've heard it might be the sharpest of all at f/1.4, but it's extremely prone to AF problems (which I'm not willing to deal with).

Not any more than other fast primes. When I tested mine against a stationary target it was more consistent in AF then Canon's 50 f/1.8 and 50 f/1.4, and just slightly less consistent then Canon's 85 f/1.8. It is on par with the L in terms of IQ and offers amazing bokeh, but is cheaper and lighter. I would recommend the Sigma out of all of them.

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