January 26, 2015, 12:00:54 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - jrista

Pages: 1 ... 69 70 [71] 72 73 ... 326
1051
Third Party Manufacturers / Re: Another Nikon full-frame
« on: August 10, 2014, 12:30:40 AM »
My guess is a D620.  It'll be what the D610 would have been if the D610 hadn't been what the D600 should have been.   ;D   I.e., they'll give something like the D810 treatment to the D610.

Yeah, that's what I figure as well. Nikon and Canon definitely take different approaches. Canon, given the 7D II saga, definitely seems to take their pretty little time designing a camera they thing will last for years. Nikon seems to iterate, make little improvements every year and release a new model.

Personally, I am not sure I'd want the camera I spent several grand on to be updated a year after I purchased it...it would be rather irksome, to think that I spent so much money on something that...wasn't done right the first time around... But, that's just me.

1052
Jrista,
Great images and informative discussion. I have learned a lot. Very confusing to noobs. I remember someone on CR frequently talking about better resolution being related to " number of pixels on target." So with reach limited subjects, you need either higher focal length lens or more (ie smaller) pixels per area on the sensor, to get better detail resolution. Did I say that correctly?

Yeah, that's correct. BTW, it's me who has always said "pixels on target". ;) I read that a long time ago on BPN forums, from Roger Clark I think, and started experimenting with it. I think it's the best way to describe the problem...because it scales. It doesn't matter how big the pixels are, or how big the sensor is...more pixels on target, the better the IQ. If you are only filling 10% of the frame, try to fill 50%. It doesn't matter if the frame is APS-C, FF, or something else...it's all relative.

1053
Your talking about on a per-pixel basis. On a per-pixel basis, that is true. However I'm talking about on a whole-image basis, or as it's called, on a "normalized" basis. When you compare images as a whole at the same size, assuming the same absolute area of sensor was used, then there won't be any difference in noise regardless of pixel size. There will, however, be a difference in detail.

This all assumes same pixel generation. The 5D III does have an advantage in upsampling due to it's newer pixel generation. It has higher quantum efficiency and overall a better pixel architecture, than the 7D pixels. That means less noise per pixel. I actually wish I had a 70D. That would make for a better comparison, as then both cameras would use sensors of similar generation, instead of being separated by over three years of technology. That's unlikely to happen unless I meet someone with a 70D who will let me borrow it for a night, though...as I have no intention of buying a 70D.

Jrista, thank you for the comparison! I found it very interesting.

I believe your experiment also shows that the current Canon FF sensors do not outresolve good lenses - contrary to some claims I've seen on this forum, essentially saying that lenses are the limiting factor and higher resolution FF sensors are pointless.

Personally, I believe the idea of a lens "outresolving" a sensor, or a sensor "outresolving" a lens, is a misleading concept. Output resolution is the result of a convolution of multiple factors that affect the real image being resolved. Sensor and lens work together to produce the resolution of the image you see in a RAW file on a computer screen...one isn't outrsolving the other. I've gone over that topic many times, so I won't go into detail again here, but ultimately, the resolution of the image created by both the lens and sensor working together in concert is closely approximated by the formula:

Code: [Select]
(1/SQRT(lensSpot^2 + sensorPixelPitch^2))/2
You can run that formula for any sensor and any lens at any aperture, and determine the theoretical maximum resolution that the two together can resolve.

1054
...certainly not as stark a difference as my first example. Maybe that one is invalid. This example, however, does show that the 7D is still picking up more subtle details and nuances of color. The differences are not stark, but they do exist.

Thanks.  This revision addresses the issue about which dak723 and I were commenting (namely, a method biased in favor of the 7D).  The difference you're showing here aligns more closely with what I've seen under similar conditions, i.e., at low ISO.  I wonder what you'd find empirically at ISO 1600 or ISO 6400...

I dunno, I guess I can try. The moon has a LOT of dynamic range. In general, a hell of a lot more dynamic range than is possible to capture even with 14 stops of DR. So I try to shoot at as low an ISO as possible. On a Canon camera, ISO 100-400 are roughly the same, there is only a fraction of a stop difference in DR between them. I chose ISO 200 in this case, as I noticed that banding was occurring at ISO 400 on the 7D.

At ISO 1600 and 6400, the biggest single problem would simply be not having enough dynamic range to differentiate fine nuances of detail, due to quantization noise. That is one area where bigger pixels do help...they reduce quantization noise, so shadow detail is better at higher ISO.

You can't think of photographing the moon as photographing something in the dark, though. It's reflecting the sun. It is an EXTREMELY bright subject, and it has massive dynamic range. (I mean, think about it...how many stops of DR do you think you would need to resolve clean, crisp detail on the dark side while simultaneously resolving clean, crisp detail in the brightest crater hotspots on the light side? At least 20 stops...although, I've tried merging a bunch of moon frames together into a 32-bit float HDR for processing in ACR...and the shadowed site was STILL too noisy...)

The issues you describe make sense.   However, in your original post you made the following point:

A common reach-limited use case is bird photography. Similar to the moon, it can be difficult to get close to and fully extract all the detail from a small songbird, shorebirds, and shy waders or waterfowl.

I believe that bird photography is a much more common reach-limited use case than lunar photography.  It would be useful to establish how applicable a demonstration of the 'reach advantage' in lunar photography is to bird photography, which comprises a broader range of conditions, frequently including subjects far less bright and/or a need for high shutter speeds.

Do you find that in general bird photography has the same demands as lunar photography in terms of DR?  What fraction of your bird images are taken at ISO 200?  A look at my bird collection shows that the median for the library is ISO 1600.

Regardless of demonstrated broad applicability to bird photography as a use case, your efforts with the moon shots are certainly appreciated!

I agree, the moon is not the same as birds. It's simply that it is a perfect reach-limited subject that doesn't zip around, constantly on the move (well, it moves, but I can track it).

Regarding birds and DR...to be honest, I have not found that dynamic range is the issue when photographing birds. Not in the sense that I've ever come across a scene where I really felt the scene contained considerably more dynamic range than my sensor could handle, even at high ISO. Usually, my bird photography is between ISO 400 and 1600, however there have been times when I've really pushed the ISO, and still gotten great results (even with the 7D...such as the Black-Crowned Night Heron photo I've shared a few times.)

One of the things I always strive for in my bird photography is getting the right angles. The right angle from me to the bird, the right angles between the bird, myself, and the sun, and the right angle of the bird's head to it's body. Those are actually very critical aspects of bird photography. When you get the right angles, then the subject is usually fully illuminated (even if it's overcast, the light still primarily comes from a certain direction) and because your angle to the bird avoids any major DR swings (i.e. having half the bird in light and half the bird on dark shadow, such as when the sun is off to your left or right, rather than behind you over one of your shoulders), even at ISO 6400 you still usually have enough dynamic range to capture the subject without issues.

There have been a few occasions when I've photographed dark birds with small very light colored spots (i.e. Belted Duck) or light birds with very dark parts (i.e. Bufflehead) where I am sometimes forced to use a lower ISO (which, to me, is probably ISO 800, maybe 400). With the 7D, sometimes ISO 400 could be problematic because of it's vertical banding issue. With the 5D III, I don't suspect it will be a problem, however for these birds, I'll probably be at 1200mm f/8, so I'd probably be using ISO 1600 instead.

Anyway, when it comes to bird and wildlife photography, dynamic range is just not an issue. It could be an issue, it probably was a few years back when I was a noob and didn't know what I was doing...but with the skill I have (and I'm not the most skilled photographer by any means, I am sure I still have many years left of learning just with bird photography, let alone wildlife, landscaps, and all the other things I like to photograph), dynamic range with birds, deer, coyotes, etc. is just never a problem. I control the lighting, as ironic as that may be to say when talking about the sun. I control it because I control the angles involved between subject, photographer, and light source. Get the right angle, and you can reduce dynamic range in the scene to practically nothing (although then your often left with a bland, uninteresting image because it has no contour, so I rarely aim for minimal DR, but I do aim to minimize it so it fits within the capabilities of my hardware), then shooting at high ISO is not a problem.

1055
Jon, thank you for the comparison and I'm not too surprised by the results.  I found it to be that way when I shot with the 7D & 5DIII side-by-side, but as soon as you hit ISO 1600 (maybe even 800) or above, the reach advantage fell apart.  Also, I found the Zone AF on the 7D to work well with AI Servo, but it wasn't nearly as good as the 5DIII.  I kept them both for a while, but like many others, sold it, keeping the 5DII and 5DIII, at least until the 1D X replaced the 5DII earlier this year.

Yeah, at higher ISO, the 5D III's newer technology and larger pixels will certainly start to show their advantage. I don't think it would be a contest at ISO 6400...but as I mentioned to Neuro, your really starting to gimp yourself with the moon, because it's such a bright subject.

I think a different test subject would be necessary to compare at high ISO. Something terrestrial, stationary, in lower light, that would really show the differences. The 7D does indeed fall apart above ISO 1600, and I don't think it would be able to keep up with the 5D III. However, I don't think the 5D III would be all that great either, as again...same absolute area.

The advantage of a full frame is it's total light gathering capacity. When you normalize subject framing, rather than subject area, THAT is when the larger frame really starts to distance itself from APS-C. For example, this photo, which is nearly a 100% crop (I think I did a little rotation and cropped out part of the top of the frame), was shot with the 5D III at ISO 12800 in the dimmer light after the sun had fully set (one of my very first photos shot with the 5D III):



I applied very minimal NR, and processing, so it could actually end up looking even better than this. Same goes for this image (shot at the same time):



When you have the opportunity of filling the frame, bigger is better. Technology still matters, and if the 7D II has vastly improved technology, the gap between it and the 5D III when the subject fills the frame will narrow, but it is highly doubtful that even the 7D II, if it moves to a 180nm process, gets a pixel count boost, gets better dynamic range, and overall better IQ...it is still unlikely that it would produce the same kind of IQ as a 5D III or 1D X or D800 or any other full frame camera.

1056
So, I thought I'd throw in a bit of a "reference image". One way to image more detail, even when seeing is bad, is to take a lot of frames at high shutter speeds, and integrate the best 10-20%. It's called Lucky Imaging (lucky, in that in some of the frames you image, you'll be "lucky" enough to have very good to perfect seeing, where the turbulence clears and everything resolves at high resolution. The exposure duration can range anywhere from a few hundred milliseconds to microseconds. In my case, I kept my exposure settings, so my exposure duration was 10ms.

I took a couple of videos of the shadowed limb of the moon at 1000 frames at 5x zoom, and integrated the best 10% (100 frames) with AutoStakkert! 2. I used the 3x Drizzle option, which is actually a superresolution algorithm, then downsampled to 50% (1.5x original resolution), so the final image is actually showing detail beyond the diffraction and aberration limits of the optics. This is the result:


(Click for full size)


I want to give this a try with the 600mm, 2x TC, and 1.4x Kenko (1680mm) on the 7D. I bet I could resolve some pretty amazing detail by resolving a few thousand frames and integrating the best 10%.

1057
...certainly not as stark a difference as my first example. Maybe that one is invalid. This example, however, does show that the 7D is still picking up more subtle details and nuances of color. The differences are not stark, but they do exist.

Thanks.  This revision addresses the issue about which dak723 and I were commenting (namely, a method biased in favor of the 7D).  The difference you're showing here aligns more closely with what I've seen under similar conditions, i.e., at low ISO.  I wonder what you'd find empirically at ISO 1600 or ISO 6400...

I dunno, I guess I can try. The moon has a LOT of dynamic range. In general, a hell of a lot more dynamic range than is possible to capture even with 14 stops of DR. So I try to shoot at as low an ISO as possible. On a Canon camera, ISO 100-400 are roughly the same, there is only a fraction of a stop difference in DR between them. I chose ISO 200 in this case, as I noticed that banding was occurring at ISO 400 on the 7D.

At ISO 1600 and 6400, the biggest single problem would simply be not having enough dynamic range to differentiate fine nuances of detail, due to quantization noise. That is one area where bigger pixels do help...they reduce quantization noise, so shadow detail is better at higher ISO.

You can't think of photographing the moon as photographing something in the dark, though. It's reflecting the sun. It is an EXTREMELY bright subject, and it has massive dynamic range. (I mean, think about it...how many stops of DR do you think you would need to resolve clean, crisp detail on the dark side while simultaneously resolving clean, crisp detail in the brightest crater hotspots on the light side? At least 20 stops...although, I've tried merging a bunch of moon frames together into a 32-bit float HDR for processing in ACR...and the shadowed site was STILL too noisy...)

1058
Very nice bird photos.I know this has been hotly debated here but I am pretty sure its the pixel size and not the sensor area that affects noise the most. My reasoning is that I have looked at images from the d800 which has aps-c size pixels and exhibits aps-c levels of noise when viewed  on a per pixel basis. That tells me that pixels of a similar size in the same generation show similar noise levels?

Your talking about on a per-pixel basis. On a per-pixel basis, that is true. However I'm talking about on a whole-image basis, or as it's called, on a "normalized" basis. When you compare images as a whole at the same size, assuming the same absolute area of sensor was used, then there won't be any difference in noise regardless of pixel size. There will, however, be a difference in detail.

This all assumes same pixel generation. The 5D III does have an advantage in upsampling due to it's newer pixel generation. It has higher quantum efficiency and overall a better pixel architecture, than the 7D pixels. That means less noise per pixel. I actually wish I had a 70D. That would make for a better comparison, as then both cameras would use sensors of similar generation, instead of being separated by over three years of technology. That's unlikely to happen unless I meet someone with a 70D who will let me borrow it for a night, though...as I have no intention of buying a 70D.

seems reasonable.

your moon photos are always a pleasure to view. it is going to be passing a bit closer than usual so hopefully the the air is clear and dry so you can get some good shots.

I probably won't be imaging the moon this weekend. I think it will be cloudy, but even if it was not...the full moon just doesn't have the same kind of interesting detail as non-full moons do. There is no shadow playing across it's surface, so a LOT of small details are invisible.

That's actually a problem with my current set of images here...you can only see detail right around the limb, and there still isn't that much there. A waxing moon is actually better, as there are a lot of interesting features when it's going from the waxing crescent phase to just about where waxing gibbous begins. I am going to start imaging the moon regularly with the 5D III and 7D at 840mm and 1200mm (and maybe even 1680mm, as I still have my Kenko TC), and maybe I'll catch it on a good night with very good seeing, so atmospheric turbulence won't be as much of a problem as it was in this set of images.

1059
Commendations on the in-depth research and comparison of the 7D and 5DmkIII.

Although the title could be a little misleading as your results do not exactly show how APS-C sensors have a reach advantage over 35mm frame sensors - but exactly how a 7D at 18mp can have a reach advantage over something like the 5Dmkx at 22mp when using the same lens for the same subject at the same distance. As APS-C sensors with less than half the pixel resolution of 35mm sensors still exist, and will likely be the case as long as the same technology is applied in both sensor designs, the ideology that APS-C will provide an advantage depends entirely on the mp/mm ratio of both sensors - not simply APS-C over full frame.

For example in Canon world (1.6 multiplier) something like the 7D would only provide the reach advantage you show as long as the smaller sensor provides at least 40% of the pixel count of the larger sensor. In other words, an 18mp APS-C sensor would have no reach advantage over a full frame 45mp sensor, because they would both produce the same resolution/data of the subject to crop for final output. Further, if the smaller sensor provided less than half the pixel count (less than 40% in the case of Canon) it would have no advantage at all as the larger sensor would have more pixels across the subject - both before and after cropping.

For some the mathematics may be difficult to follow as Canon does not have anything even close to 45mp (not even half that currently) so we can use another brand like Nikon. The 12mp APS-C sensor of say the D300s, or the 16mp APS-C sensor of the D7000, provide no reach advantage over their 36mp FX bodies because even with the subject only covering a ~50% region of the sensor it is still resolved by more mp than the APS-C sensors.

Still a very informative research project within the offerings of one manufacturer.  :)

You are correct, this is really less of APS-C vs. FF as it is small pixels vs. large pixels. It really doesn't matter if the small pixels are in an APS-C sensor or a full frame sensor...they could all be in an MFD sensor. The actual size of the frame really doesn't matter. What matters is the size of the pixel. It just so happens that smaller sensors tend to have smaller pixels...so it still holds true that APS-C sensors have reach advantages over FF sensors.

The exact advantage is indeed relative to the specific sensors involved. The 7D probably wouldn't show any advantage over a D800 if they were compared like the image in my last post. The D800 has vastly superior sensor technology, so even though it's pixels are slightly larger, all that technology is going to trounce the 7D. The difference between the 7D and 1D X is going to be more significant than the difference demonstrated here between the 5D III and the 7D. That's a given, I think everyone understands that.

I'd just been asked in the past to prove my case with actual images, instead of just theory and math, as I've often argued that the smaller pixels will always have a resolving power advantage over larger pixels. I am simply trying to fulfill my promise here, and provide some actual images to back up my claims. The advantage isn't wildly huge...I've never claimed that. It's a nuanced advantage, for sure. But the advantage exists, nevertheless.

BTW, you brought up some differences between some older Nikon cameras and the new 36mp FF cameras. I'd like to point out that you failed to account for Nikon's newer APS-C parts. Nikon has several 24mp APS-C cameras that maintain the balance, and preserve the reach advantage of the smaller sensors over larger sensors. A 24mp Nikon APS-C is going to have a similar reach advantage over a 36.3mp D800 or D810. Both the smaller and larger sensors use the same technology, same generation of sensor...so the only key difference is pixel size. Assuming the subject fills the same absolute sensor area...on a normalized basis, the differences in noise will be minor but the differences in detail will be measurable.

1060
............
 I've long held the opinion that crop sensor cameras, like the 7D, do have value in certain circumstances. The most significant use case where a camera like the 7D really shows it's edge over full frame cameras is in reach-limited situations.

............

I'd like to prove my case

................

Both images were initially scaled to approximately 1/4 their original size (770x770 pixels, to be exact).

The 5D III image was then layered onto the 7D image, and upsampled in Photoshop by a scale factor of exactly 161.32359522807342533660887502944%.



While I agree with you that a 7D (or any so called crop sensor) can have advantages over a so called full frame sensor. I think you need to review your work if your objective is to reach a valid conclusion.

1) you start off with a strong opinion. (its better to have an open mind)
2) Then you try to "prove my point". (it might be better to try to test your opinion)
3) Then you do something that is going to be very detrimental to one of the images.

You may claim that you would have to upsample the 5D3 image to get the same size as the 7D. But you have already down sampled it - so you have lost detail in the 5D3 file.

To demonstrate I made a simple file in Photoshop. 770 pixies  ;D wide, copied it, scaled it to 481 wide, then upscaled it to 770 wide. Hardly by chance my file had two types of detail. A sharp line and a not so sharp line. The result can be seen below.

I think I have just proved that photoshop is better than photoshop.  >:(

Don't get me wrong I'm a fan of the 7D and think its a great camera. I also think there is a place for "crop sensors". I'm waiting for the 7D2, I don't think it will be for me, but I definitely see a crop sensor shaped hole in my kit.

and finally whats with 30 odd decimal places!


EDIT: Just in case anyone wonders  ;D  the down sampling and up sampling were done with default PS settings

You are correct. However, the image below was actually done a bit differently. In this case, both samples were downscaled to fit in the 770x770 pixel image...the 5D III image was not first downsampled then upsampled again.



Your right, certainly not as stark a difference as my first example. Maybe that one is invalid. This example, however, does show that the 7D is still picking up more subtle details and nuances of color. The differences are not stark, but they do exist. Also note, both of these images were denoised. They were both denoised to the point where they both exhibited about the same noise levels...where noise was pretty much not visible. Obviously, there was quite a bit less noise reduction applied to the 5D III image.. That actually costs the 7D a little bit of it's detail as well...but it is on a level playing field with  the 5D III as far as noise goes, so I still think it's a fair example.

1061
Very nice bird photos.I know this has been hotly debated here but I am pretty sure its the pixel size and not the sensor area that affects noise the most. My reasoning is that I have looked at images from the d800 which has aps-c size pixels and exhibits aps-c levels of noise when viewed  on a per pixel basis. That tells me that pixels of a similar size in the same generation show similar noise levels?

Your talking about on a per-pixel basis. On a per-pixel basis, that is true. However I'm talking about on a whole-image basis, or as it's called, on a "normalized" basis. When you compare images as a whole at the same size, assuming the same absolute area of sensor was used, then there won't be any difference in noise regardless of pixel size. There will, however, be a difference in detail.

This all assumes same pixel generation. The 5D III does have an advantage in upsampling due to it's newer pixel generation. It has higher quantum efficiency and overall a better pixel architecture, than the 7D pixels. That means less noise per pixel. I actually wish I had a 70D. That would make for a better comparison, as then both cameras would use sensors of similar generation, instead of being separated by over three years of technology. That's unlikely to happen unless I meet someone with a 70D who will let me borrow it for a night, though...as I have no intention of buying a 70D.

1062
Reviews / Re: DxO reviews Sony A7s: king of low light photography?
« on: August 09, 2014, 04:03:09 PM »


Except...they store the output in a lossy image format. Until Sony fixes that, at the moment, I don't think there is any significant difference between the A7s and 1D X for still photography. The big differences show up with video...the A7s thanks to the BionzX processing, does indeed do wonders at ultra high ISO video.

I think you exaggerate the influence of the lossy compression. It creates some very visible artifacts in very specific cases when you push the files, in around 3800 images with my A7R I have seen the artifacts in exactly 1 image. In the rest I doubt you could tell which one is which had both the compressed image and the uncompressed been available.

But I think they should make a uncompressed option, which they could easily do with a firmware update. But the A7 cameras have also a lot of other silly firmware limitations and honestly I'd be surprised if Sony bothers fix them. There will never be a perfect camera.

It isn't the artifacts. It's the fact that the compression is lossy. They are throwing away information. It's the original depth of information that makes Sony Exmor so great. Why, then, would you throw away some of that extra precision? Sony cameras, when tested, don't achieve the same levels of DR as Nikon cameras with the same sensors...so clearly, Sony is losing something by using their compressed RAW format. Because it's lossy, it doesn't even qualify to be called RAW...it isn't RAW! :P

1063
I have been using macbook retina's for awhile strictly running windows since the screen covers the rgb gamut and is very accurate. I just bought a thinkpad w540 with the 3k display. It covers 97% so close enough but the pics just do not have that pop the had with the retina since the thinkpad has an antiglare coating. The pictures look flat and the mac makes the appear to have more saturatiin. Does anyone here edit with a matte coated screen thqt has worked with a macbook that could tell me your experience? I am afraid the macbook is the better screen but I never run osx.

You should look into the Dell XPS 15. I just purchased the XPS 15 with 3200x1800 screen, 500GB SSD, and 16GB ram. The screen is amazing. It had a slight greenish tint at first, but after calibration, it's wonderful. It has a reflective screen, which honestly I don't like that much...it glares all over the place, which is actually worse than having an antireflective screen.

I really wish that manufacturers would start using some kind of multicoating on glossy screens. That way we could have the best of both world...very low glare, but still have that crisp, crystal clear detail.

Anyway, the Dell XPS 15 is a phenomenal laptop. It's extremely fast, has enough memory to do just about everything, and the screen is very, very nice.

1064
I've said it so many times, I know others have also said it. Noise is relative to the area, not the pixel. If two cameras use the exact same area of sensor to resolve a subject, then there is no difference in noise. Not when the image from the sensor with smaller pixels is downsampled to the same dimensions as the image from the sensor with bigger pixels.

So then why do you keep questioning DxO sensor normalization? What you just described above is exactly the same thing. So why do you get it in one context, but not in the DxO context?

We've had this argument. We've had it countless times. You know the answer. I've been extremely detailed and clear about my opinions, and exactly what my opinions are. I'm NOT going to let you ruin this thread by diving into another pointless discussion of DXO. You want to have that debate, please, don't ruin my thread...start another thread. PLEASE.  >:(

Everyone, let's keep DXO out of this discussion. This thread has nothing to do with comparing Canon and Nikon cameras or anything like that. It has to do with the reach advantage of smaller pixels. That's it. I don't want this thread to be derailed by another useless debate that we've all had ten thousand times.

1065
Reviews / Re: DxO reviews Sony A7s: king of low light photography?
« on: August 09, 2014, 03:43:32 PM »
...
The Sony A7s is king of the hill at the moment when it comes to low light performance. It has better high ISO than anything else out there. On top of that it has class leading DR - not as good as Nikon but definitely better than anything Canon currently has to offer.

All that the A7s needs now is a reasonable selection of lenses.

A question that many will be asking is whether the A7s will be beaten on high ISO. That's hard to figure and quite possibly not, even by its successors - or at least for bayer sensors. The reason for that is fewer, larger, pixels and that is something that a lot of people have been screaming for.

"Give me fewer pixels but make them better (bigger)" is often heard in internet forums.

Well now Sony has done just that and hasn't it delivered.

Fewer, larger pixels don't have anything to do with it. Pixel size has never really had anything to do with it. Sensor size, quantum efficiency, and fill factor are what really affect it.

And how do you get more electrons in the pixel? By making it bigger.

More electrons per pixel is a facade. Let's say I have 10µm pixels and 5µm pixels. The large pixels gather 200ke- at FWC. The small pixels gather 50ke- at FWC. The bigger pixels win, right?

Sorry, wrong. Bin four 5µm pixels, and what do you get? 50ke- + 50ke- + 50ke- + 50ke-. That's 200ke-! Pixel size does not matter. Assuming you put the same ABSOLUTE SENSOR AREA onto your subject, it doesn't matter what size the pixels are...your still going to be gathering the same amount of light in total.

When you throw in fill factor, the 5µm pixels won't quite get 200ke- light in total. It might be something like 195ke- or so. That is still a very small difference, about 2.5%. Overall, smaller pixels still gather the same amount of light as larger pixels, if you put the same absolute sensor area on the subject.

Pixel size isn't what matters...the underlying technology is what matters. The efficiency of the sensor, the rate at which it accumulates dark current, the readout mechanism and how much downstream noise it introduces. THOSE are what matter. In that respect, Sony definitely has the better technology (no one questions that.)

Quote
I'm guessing the high low ISO read noise was some kind of tradeoff necessary to achieve the clean high ISO.

Or maybe not clean high ISO but how to get the data off the sensor fast enough to do 4k video. Whatever it is a decision that Sony made.

Indeed. Similar to the decisions Canon made when they decided to make the 1D X and 5D III excellent high ISO performers that are capable of handling very high still photography frame rates. The data throughput requirements to chomp through 14 18mp images per second is similar, if not higher than, the data throughput requirements to chomp through 4k video.

But, it's ok when Sony makes such a decision, and not when Canon does? (That's all I can gather from your history here on CR...)

Quote
Anyway, pixel size has little to do with it. Transistor size has a small impact...it affects fill factor, especially as pixel count goes up, however a relatively "low" pixel counts of 18mp and 12mp, the difference in transistor size is minor.

I don't know how to respond to this. It's all just wrong. Transistor size is related to the lithographic process used to create the sensor. Thus a 12MP and 18MP can have exactly the same size transistors whilst having different size pixels. Now there is a "fill factor", if you like, where space taken by a transistor and its traces is not available to a pixel.

But since you've raised the topic of transistors, yes, Canon still has larger transistors than Sony and that's not a good thing.

No, Canon's larger transistors are not a good thing. I totally agree they need to improve their manufacturing process. Actually, they already have...Canon has been using a 180nm copper interlink design with lightpipes for their small form factor sensors for years now. Who knows why they haven't employed it on their larger sensors.

As for fill factor, the difference that larger or smaller transistors make with such large pixels is small. It's there, certainly, but it is not the most significant factor. It doesn't come even remotely close to the 20% difference in quantum efficiency. THAT is a truly major breakthrough, to achieve 67% Q.E. at room temperatures. It's the increase in quantum efficiency that really gives the A7s the edge here. Combine 67% Q.E. with Sony's better readout system, and yea, it's going to be a hell of a performer.

Except...they store the output in a lossy image format. Until Sony fixes that, at the moment, I don't think there is any significant difference between the A7s and 1D X for still photography. The big differences show up with video...the A7s thanks to the BionzX processing, does indeed do wonders at ultra high ISO video.

Pages: 1 ... 69 70 [71] 72 73 ... 326