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Messages - jrista

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1156
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.

It is not true as a general statement that the more pixels on target, the better. There have to be optimum sizes of pixels and optimal numbers on target, as shown by the following arguments. The signal to noise of a pixel increases with its area: the bigger the pixel, the greater the number of photons flowing through it and the greater the current generated, and the statistical variation in both becomes less important.

True. However that does not falsify my claims about pixels on target. We don't look at pixels. We look at images. Noise is relative to area. If you take 6.25µm pixels and 4.3µm pixels, you can fit 2.1 of the smaller pixels into every one of the larger pixels. Assuming the same technology (which is not actually the case with the 5D III and 7D...but humor me here), those 2.1 smaller pixels have the same amount of signal, and therefor the same amount of noise, as the single larger pixel. Noise is relative to area. If you increase the area of the sensor which your subject occupies, you reduce noise as a RELATIVE FACTOR.


The dynamic range is also greater for large pixels than can accommodate a large number of electrons. A low megapixel sensor should have very good signal to noise and DR, but poor resolution. Now, see what happens as we progress to the other extreme. As, we decrease the size of the pixel, the resolution increases but the statistical noise starts to increase as the number of photons hitting each pixel decreases per unit time.

Per-pixel noise is an absolute factor. You are absolutely right that larger pixels have less noise and higher dynamic range. However ultimately, to maximize IQ, you don't want to achieve some arbitrary balance between pixel size and pixel count. You simply want to maximize the number of pixels on subject, regardless of their size. Because it really isn't about the pixels...it's about the area of the sensor your subject occupies.

In a reach-limited situation, the absolute area of the sensor occupied by your subject is fixed...it doesn't matter how large the sensor is. You will be gathering the same amount of light in total for your subject regardless of what sensor your using, or how big it's pixels are. Therefor, the only other critical factor to IQ is detail...smaller pixels are better, in that case, all else being equal.

The electrical noise also increases until the inherent noise in the circuit becomes greater than that due to the fluctuation in number of electrons generated by the photons. We all experience this as the noise caused by increasing the iso setting. The dynamic range also decreases. Eventually, the pixel becomes so small that it loses all of its dynamic range because the well is so shallow it can hold only a few electrons.

Actually, electronic noise within the pixels themselves, ignoring all other sources of read noise (which tend to be downstream from the pixels) is due to dark current. Dark current noise is relative to pixel area and temperature...and dark current noise DROPS as pixel size drops. The amount of dark current that can flow through a photodiode is relative to it's area, just like the charge capacity of a photodiode is relative to it's area. So, technically speaking, electronic noise does not increase as pixel size decreases. Again, dark current noise is relative to the unit area...pixel size, ultimately, does not matter.

When it comes to read noise overall, that actually has far less to do with pixel size, and far more to do with the downstream pixel processing logic, how it's implemented, the frequency at which those circuits operate, etc. Most read noise comes from the ADC unit, especially when they are high frequency. I've seen read noise in CCD cameras that use Kodak KAF sensors change from one iteration to the next. A camera using a KAF-8000 series had as much as 40e- read noise a number of years ago. The same cameras today have ~7e- read noise. They are identical sensors...the only real difference is read noise. That's because read noise isn't a trait inherent to the sensor...it's related to all the logic that reads the sensor out and converts the analog signal to a digital signal. Canon could greatly reduce their read noise, without changing their sensor technology at all...because the majority of their noise comes from circuitry off-die in the DIGIC chips.

So, too large a pixel gives too little resolution, too small a pixel gives too much noise and too small dynamic range. You could have a 20 billion too small useless pixels on target where 20 million would be the optimal number. Because of the above reasoning, astrophotographers and astronomers match pixel size to their telescopes. For photographers, the optimal size for current sensors pixels is around the range of crop to FF.

Your ignoring the fact that you can always downsample an image made with a higher resolution sensor to the same smaller dimensions as an image made with bigger pixels. The 7D and 5D III are the cameras I used because they are the cameras I have. I often use the term "all else being equal" in my posts, because it's a critical factor. The 7D and 5D III are NOT "all else being equal". They are a generation apart. The 7D pixels are technologically inferior to the 5D III pixels.

So, ASSUMING ALL ELSE BEING EQUAL, there is absolutely no reason to pick larger pixels over smaller pixels, assuming your going to be framing your subject the same with identical sensor sizes. If your photographing a baboon's face, and you frame it so that face fills the frame with a nice amount of negative space. If you have a 10mp and 40mp camera, You should ALWAYS pick the sensor with smaller pixels. You can always downsample the 40mp image by a factor of two, and you'll have the same amount of noise as the 10mp camera. Noise is relative to unit area. It doesn't matter if that unit area is one pixel in a 10mp camera, or four pixels in a 40mp camera...it's still the same unit area. Average those four smaller pixels together, and you reduce noise by a factor of two. Which is exactly the same thing as binning for pixels during readout, which is also exactly the same thing as simply using a bigger pixel.

The caveat, here, is that with a 40mp sensor, you have the option of resolving more detail. You plain and simply don't have that option with the 10mp sensor. More pixels just delineates detail...and noise...more finely. Finer noise has a lower perceptual impact on our visual observation. If the baboon face is framed the same, then your gathering the same amount of light from that baboon's face regardless of pixel size. Photon shot noise (the most significant source of noise in our photos) is intrinsic to the photonic wavefront entering the lens and reaching the sensor. Smaller pixels simply delineate that noise more finely.

1157
+1 My biggest mistakes are when my camera is set for point exposure for birds against a normal background and one flies by against the sky and I don't have time to dial in +2 ev to compensate or vice versa. Two more stops of DR would solve those problems.

This is a case where you want more DR to eliminate the need for the photographer to make the necessary exposure change. If you encounter this situation a lot, I highly recommend reading Art Morris' blog, and maybe buy his book "The Art of Bird Photography". He has an amazing technique for setting exposure quickly and accurately, such that making the necessary change quickly to handle this situation properly would not be a major issue.

Personally, I wouldn't consider this a situation where more DR is necessary. It might be a situation where more DR solves a problem presented by a lack of certain skills...but it is not actually a situation where more DR is really necessary.

1158
You won't?? Even if you use say a 7D and a 5D2 and the 7D sensor is more efficient at collecting and converting photons per area of surface than the 5D2?? With the 7D you can chose to get either: more detail (unless conditions are super bad) and more noise OR slightly better detail with less de-bayer and other artifacts and slightly better noise (if you view or convert to same scale as the 5D2).

Unfortunately it doesn't work that way in crepuscular conditions.  You can have all the "pixels on target" you want, but if the sensor can't handle the low lighting (7D), you're not going to get the shot. And by "shot", I mean something you can print at 16x20.

When shooting in RAW during the November white-tail rut in Montana, my 7D becomes almost useless. The sun comes up at 8:30, and light gets shaky around 4:30 thanks to consistent, thick cloud cover. It's often snowing or raining.  Once I start hitting 1600 ISO on the 7D, it's time to put it away. Out comes the full frame, where I can get usable images at ISO 12,800. Not to mention that my other cameras do a  much better job of focusing on low contrast targets (brown deer with a brown background) than the 7D.

In these cases, noise is the bottleneck.

Regarding birds and DR...to be honest, I have not found that dynamic range is the issue when photographing birds.

So two golden eagles swooping in to take out a bald eagle at your back, silhouetted in the sun doesn't present a DR issue? What about bighorn rams fighting each other in uneven forest light? People wait all year for those moments, heck, they wait years. A second later, it could be gone.

Dynamic range is the single biggest issue with wildlife photography, IMHO. That's why the shadow recovery in the Sony sensors is so appealing.


Quote
Anyway, when it comes to bird and wildlife photography, dynamic range is just not an issue.


I completely disagree.  It's the issue. Are you going to sneak around a grizzly bear in the bushes to get the right angle? (that's a great way to get yourself killed). Or how about tramping in the willows on a mountain lake to get just the right light on a bull moose? (another good way to get killed).  What about when a squirrel decides to watch sunrise over Glacier Point in Yosemite? Are you going to command the sun to rise from the west so you can get the good light? If you are shooting tame birds or zoo animals, maybe it's not much of an issue. But for actual wildlife? Top of the list.

The only one with the control in wildlife photography is the animal. They do what they want, when they want, and under the lighting conditions they see fit. It's your job to take the punches and get to the 12th round.

I decided to combine your two posts, because I think the context of the two matter here. First, you talk about crepuscular conditions. You have brought that up a couple times in the past as well, and it is a valid point. However I think it is a point at odds with the points you make in the second post.

In crepuscular light, the low light around sunrise and sunset, you are NOT going to be using ISO 100 or 200. As you say, your going to be up at ISO 12800. You need the high ISO so you can maintain a high shutter rate, so you can freeze enough motion to get an acceptable image. There are times during the day when you can capture wildlife out and about, but the best times are indeed during the crepuscular hours of the day.

Just for reference, here are the dynamic range values for four key cameras at ISO 12800:

D810: 7.3
D800: 7.3
5D III: 7.8
1D X: 8.8

As far as dynamic range for wildlife and bird photography during "activity hours" goes, there is no question the 1D X wins hands down. It's got a 1.5 stop advantage over the D800/D810, the supposed dynamic range kings. At ISO 6400, we have:

D810: 8.3
D800: 8.3
5D III: 8.5
1D X: 9.7

At ISO 3200 we have:

D810: 9.2
D800: 9.2
5D III: 9.5
1D X: 10.5.

At ISO 1600 we have:

D810: 9.8
D800: 9.8
5D III: 10.1
1D X: 10.8

And finally, at ISO 800 we have:

D810: 10.8
D800: 11.2
5D III: 10.5
1D X: 11.1

It is not until we reach ISO 800 that the D800 series cameras start to close the cap and overtake the high ISO advantage of Canon cameras high ISO DR. It is certainly possible to shoot at ISO 800, and ISO 400, in the hour leading up to sunset...I have shot at those settings myself. However shadows are long during that hours, and it is more common that I am shooting at a higher ISO. It is only the hour or two around the two-hour period of midday that I ever find myself shooting at ISO 100 or 200...and then, it is rarely with fast moving subjects like a Golden Eagle flying directly at me to fight with another bird behind me. I'd again be at a higher ISO to guarantee I have the shutter speed I need to capture that action with just the right amount of motion blur in the wing tips, but otherwise freezing the motion of the bird itself.

Regarding pixels on subject...I'm confused why you would say that doesn't matter. If you increase the size of your subject relative to the size of your pixels, that means that the frequency of the noise becomes higher and higher relative to the subject. It really doesn't matter if you are at a higher ISO or not...the frequency of noise is still based on the pixel pitch. If I take two shots of a deer, at ISO 12800, and in one the deer fills 33% of the frame and in the other the deer fills 66% of the frame. Which image is going to have better IQ? The one where the deer fills 33%? No, of course not. The image where the deer is larger in the frame...the image where there are "more pixels on the deer", is going to have the better IQ. The deer is much larger, so all that ISO 12800 noise is going to be less intrusive, as in terms of relative frequency, the noise is much smaller.

Whether the 7D is useful or useless depends on exactly that. Pixels on subject. I've been able to make very good use of my 7D under very difficult lighting conditions by taking the time to get the subject framed right, and getting it frames large enough. Even at very high ISO:



This night heron was shot at ISO 3200, but underexposed by about a stop (I'd had my 7D configured to limit which ISO settings would be automatically selected at the time, and I was shooting Auto ISO). The shutter speed was 1/6th second. This was with the 600mm f/4 L II, well after sunset...blue hour was on, and there were dark clouds blocking a lot of the remaining post-sunset light. The only reason I was able to make anything of the shot and still have this much detail was because I managed to get enough pixels on the bird that it could withstand the editing.

So, first off, I do not believe that the argument that the enhanced DR of the Sony sensors is useful when it comes to wildlife or bird photography. On the contrary, given the measurements, it seems like the Canon cameras do indeed have the DR edge, especially the 1D X, and especially at the higher ISO settings that are critical during the hours wildlife is most active.

To address a couple points more specifically. The silhouette scene...a bird silhouetted is a bird silhouetted. Either it is a dark subject against a very bright background, or it's not. If we are talking about something where a bird is silhouetted against bright sunlit water, even a D800 is going to struggle with that....assuming you even had the option of shooting at ISO 100. The likelihood is that your using a much higher ISO (pretty much GUARANTEED in the "two golden eagles flying in with the sun at their backs" case) in which case there is no advantage to using a D800 or having more DR. In that situation, you do something like this:





You make the images REAL silhouettes...pure shadow superimposed over a brighter background.

When it comes to other animals, like bull moose or elk, bears, or the squirrel that wants to watch sunset. Well, starting with the squirrel...I would certainly do what I could to get on the western side of it. I mean, we are talking about good lighting here, lighting that does your subject justice. Aside from silhouetting your subject, shooting from the back side directly into sunlight is not the most flattering light for a wildlife subject. It might make for one interesting photo one time, but in general, I look for the scenes and angles where my subjects are better lit. The sun does not necessarily need to be directly at your back. Actually, having the sun DIRECTLY at your back is not good either, as it flattens your subject. There needs to be a certain angle, and sometimes you can suffer a little bit of loss on the DR front (i.e. end up with slightly too much DR in the scene than you can really handle) in order to get a shot that might otherwise not be possible.

Regarding moose, elk, deer, etc. I absolutely do what I can to get a better angle on them. But you pick  your battles, for sure. Deer, elk, etc. are quite docile during the earlier parts of the year. It is only really during the rut and their mating season that they take on a hostile stance. That is where having a big long lens, and some TC's and, maybe even, a cropped sensor, become really handy. They give you a much more comfortable working distance when photographing rutting wildlife.



Here is an example where I did what I could to get the right angle of light, during crepuscular hours. Light still coming from more of an angle than I wanted, the elk's body is decently lit but the beard is more shadowed than I wanted, but shot still came out quite nicely. In this particular situation, for the given exposure, a D800 would not have offered me much in the way of advantages over the 7D...I was reach limited, I was at very high ISO. The D800 might have had slightly more DR, but less resolution, and similar per-pixel noise...but a considerably slower frame rate.

So, at least in my experience, given that I rarely have the opportunity to shoot wildlife of any kind at ISO 100, and were not talking about zoo animals here, but real WILD life...I do not believe DR is a critical issue with wildlife photography. You simply don't have 12 or 14 stops at ISO settings from 400 and up. At the really high ISO settings we use during crepuscular hours, ISO 3200, 6400, even 12800, we might not even have EIGHT stops of DR! I also do not believe it is impossible to situate yourself, the photographer, at the right angle to your subject such that it is properly lit, therefor minimizing or eliminating DR issues in the first place. Even in the cases where DR might become an issue, such as backlit subjects...if you look at the photography of well-respected wildlife pros, like Andy Rouse...he doesn't try to lift the shadows of a shaded backlit subject like an African wildcat by many stops. He leaves them shaded, he leaves them contrasty. Sometimes it just isn't about dynamic range...sometimes, dynamic range really, truly, doesn't matter...

1159
Hi,
   Today, I do a compare shots on FF vs APS-C on a real bird under real life condition... only manage to try out ISO 1600 and ISO 3200 as start to rain very heavily after this. I just open them using lightroom 4, took a screenshot, paste on paint and saved as jpeg.
Test Condition
Camera: Canon 6D (left) vs Canon 60D (right)
Lens: Tamron 150-600mm @ F8
Subject: Stork-billed Kingfisher at around 18m (this is the only real bird that I can find that will stay at the same place for extended period of time with minimum movement).
Weather: Cloudy

After looking at the compare shots, my initial conclusion is that the 60D sensor doesn't seem to have a significant details advantage (if any) under real life condition (at least this seem to be true when using the Tamron 150-600mm lens) over the 6D and the 6D (up to ISO 3200) doesn't seem to have a real noise advantage if the 60D image was scale down.

   Have a nice day.

PS: The CanonRumors website seem to scale down the screenshot image (actual size is 1920 x 1080) to fit the website frame... to view at actual size, need to click on the image and using the scroll bar below the post to scroll through the image... or is there a setting to show the image actual size??

Very interesting results. Congrats on finding a bird that would sit still the entire time you took the shots. :D That's definitely the kind of bird you need.

To really truly compare, you would need to overlay the two images on top of each other, and upscale the 6D images so the bird was the same size, then overlay them directly on top of each other (Photoshop's difference layer blending mode makes the positioning very easy). Then you can swap back and forth, and really see the difference. It's pretty much impossible to objectively determine any real differences when looking at the images side-by-side...it becomes almost a pure subjective judgement.

The only other thought I have is the lens used. The 150-600 is a good lens for it's price class, but I can tell it does not resolve the same kind of detail as the EF 600 f/4 II. I am able to resolve fine feather and fur detail even at very high ISO, something I don't see in your images. It doesn't necessarily invalidate the test, however it does throw in a major factor that affects results. The moon is a bit of a different kind of subject than a bird, given that it is primarily seeing limited rather than diffraction limited, so using 1200mm f/8 does not limit resolution the way it would with a terrestrial subject. If I were to do a bird test...I would probably use the 600 at f/4.5, which seems to be the absolute sweet spot of my lens.

1160
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%.

I wish I had the processing skill and knowledge you do! It's impressive how much detail you can pull out at these focal lengths. I went the other way, increasing FL until I got results I was content with, although eventually the extra glass (stacked teleconverters) degrades image quality and it seems to even out. Still, I feel more data can be pulled out of my setup, if only I knew how.

Good stuff, as ever.

It's actually not difficult. AutoStakkert! 2 pretty much does all the work. You record a video, and since the moon in each frame is moving a little bit...due to atmospheric turbulence and due to it's transit across the sky (unless you have a tracking mount...then it will move a little bit due to periodic error of the mount), the position of the moon and its features change just a little frame to frame. That allows advanced algorithms to be used to figure out what the "right" value is for each pixel, and even enhance resolution by using superresolution algorithms like drizzle. All you really have to do is record the video, and perform three steps in AutoStakkert! (load image, analyze, stack).

1161
Third Party Manufacturers / Re: Another Nikon full-frame
« on: August 10, 2014, 01:51:04 AM »
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.

Canon does that, too, at least in the Rebel line.

T1i: 2009
T2i: 2010
T3i: 2011
T4i: 2012
T5i: 2013

Can the T6i be far behind?

The rebel is different. It's marketed at a type of consumer group that expects products to remain up to date. Totally different, IMO, than more professional products like the D610 and D810 or 5D III.

1162
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.

1163
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.

1164
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.

1165
...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.

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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.

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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%.

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...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...)

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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.

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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.

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