Full Frame and Bigger Pixels vs. APS-C and Smaller Pixels - The Reach War

[jrista]

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.

 

[neuroanatomist]

...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!

 

[jrista]

...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.

 

[neuroanatomist]

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

...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.

I haven't found DR to be limiting, either. Noise at high ISO, on the other hand, I have found limiting with the 7D. Overall since getting the 1D X, I am using higher ISOs for birds, and still getting less noise. I strove to keep the 7D under ISO 1600...with the 1D X, that bar has gone up to ISO 6400. One consequence for example is that now, artistic wing blur is a choice rather than a concession.

 

[roguewave]

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.

 

[jrista]

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:

(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.

 

[serendipidy]

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?

 

[LetTheRightLensIn]

...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...

Noticeably more detail on a Hairy Woodpecker at something ISO1600-2500. Noticeably more detail on a dollar bill at ISO6400 (this one was of course a high contrast subject in a well lit portion of the frame, so for a camera like the 5D3/1DX (although NOT 5D2) at some point if the subject is enough of a combination of low contrast, dark coloration, in a dark part of the frame the reach advantage might go away and the overall look might eventually end up nicer with the 5D3/1DX).

 

[LetTheRightLensIn]

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.

That really wouldn't even make sense if you think about it properly. Sure FF cams have more MP, but the MP are spread over such a much larger area that they have lower density than current APS-C cameras. It should be the aps-c cameras where such a limitation is to be first noticed.

It's not some sudden limit kinda thing though. You can see that even the crummy lenses on say photozone.de, that lag behind on some old camera they test with low density, nonetheless often give a final result on a high mp camera that is more more lines per inch. At some point though with a poor enough lens and high enough density the gains will fade to nothing of any significance though (and quite a few lenses already hit that point at FF extreme edges and corners even at current densities, many if talking about wide open)

 

[jrista]

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.

 

[scyrene]

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.

 

[100]

Nice comparison. Thanks for posting.
They were both shot with the same settings and the same processing in Lightroom and I wonder what happens if you use the best settings and most optimal processing for each camera/image.

With more than two and a half times more light, it's two and a half times better. Like using two and a half stops lower ISO on the cropped sensor.

Double the light is one stop so 2.6 times the light is about one and a quarter stops.

You are correct about the number of stops. My mistake.

As for settings...what would be better settings? I mean, exposure is exposure...and technically speaking, using the same ISO means the 5D III has the advantage, no? I used ISO 200 for both shots...the larger pixels of the 5D III should mean that much more light is gathered per pixel at ISO 200 (which is indeed the case, noise comparison coming.)

So, I honestly don't think I could have used any better settings on the 5D III. And exposure is exposure...it's light over time...for a given subject of given brightness, you have to use the same exposure.

The DLA of the 7D is f/6.9 so shooting at f/8 is theoretically not the optimal f-number and iso 160 seems to be the cleanest iso for the 7D.
My experience with the 18mp crop sensor versus the 22mp FF sensor is that they need different processing in ACR (noise reduction, sharpening, etc.) for optimal results.

Another thing about ISO. A FF sensor is 2.6 times bigger, so it can gather 2.6 times the amount of light, but if your subject doesn’t fill the sensor area and everything around it is basically black with the same lens and the same settings the total amount of light hitting the sensor will be the same for both sensors, so there is no ISO advantage due to sensor size. The 5DmkIII gets more light per pixel due to bigger pixels but has less pixels on the subject. However these camera’s don’t have the same generation pixels and in camera processing so the 5DmkIII will perform better as far as noise in concerned. The 7D will perform better on resolution/detail and by the looks of it you gain more detail with smaller pixels than you lose with the higher amount of noise reduction needed. At least at low ISO setting.

 

[weixing]

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

Below are the shots:

6D vs 60D ISO 1600 (1:1)

6D vs 60D ISO 1600 (2:1)

6D vs 60D ISO 1600 (1:0.5)

6D vs 60D ISO 3200 (1:1)

6D vs 60D ISO 3200 (2:1)

6D vs 60D ISO 3200 (1:0.5)

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??

 

[Northstar]

All this makes me salivate for a 7D2, and also a large MP FF that I can get more reach with...

 

[Lightmaster]

thx for the tests.

 

[docsmith]

Another 7D to 5DIII convert here. I don't dispute that the 7D could out resolve the 5DIII in certain circumstances. Your second comparison with the moon is more inline with my tests than the first. But as I was evaluating the two bodies, for me, it became more than just about resolving power. The color, transition from the highlights and blacks, noise, etc, were what stood out to me as the primary differences.

The 7D is an amazing camera. I shot with it for years. I would not hesitate to recommend it.

And I make this post knowing this thread is titled "The Reach War," but I was a little surprised that no one else had yet brought up that the differences between the 5DIII and 7D (or 70D) is about more than reach and noise.

That said, I will watch reviews and comments on the 7DII. It would be nice to have the extra reach if everything else is up to speed. The 7DII with a 100-400L would be easier to travel with and cheaper than a 600 II. But, I haven't shot my 7D since the early tests with the 5DIII. Even for birds. I prefer the shots taken from the 5DIII. Sometimes I miss the reach, but, overall, I prefer the images.

 

[MichaelHodges]

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.

 

[MichaelHodges]

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.

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.

 

[AlanF]

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.

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 sunset 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.

+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.

 

[AlanF]

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. 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. 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.

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.