1DS3 vs 5D CoC shootout in MFDB forum

[ejmartin]

Emil, I read your post but I didn't pick up on it in relation to Doug's latest question because he SEEMS (if I understood correctly) to be concerned about the resolution of out-of-focus image areas and this makes me wonder what the point is - seems to me that the resolution at which one sees these out of focus regions is hardly determinative of image quality.
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I see, I didn't read his post carefully enough.  I agree with what you say.

[joofa]

Yes, but I presume that Bill was shooting a test target, which have sharp edges or sinusoidal variation with spectral power out to high frequency.  A proper test target used in a proper test methodology should not in and of itself limit the MTF as a function of spatial frequency, otherwise the testing methodology is flawed.  Are you saying that Bill's measured MTF50 is inaccurate?

In theory,  the MTF of a sensor can't be defined because such a system is not shift invariant. I know that even in this case people like to call the Fourier response of the sampled output of a point input as MTF, though it is not correct. However, solutions do exist that provide rigor to such traditional MTF methods by taking into account the shift-variant dependences that sampling produces by defining shift-invariant sampling MTF as an ensemble average over all possible positions of the scene with respect to the sampling locations.

[dwdallam]

You're talking about the comparative resolution of blurred images shot with the same lens, same settings between these two cameras? Have I understood the question? The extent of blur should be identical and I'd be hard-put to imagine visible differences of resolution through the blur between these cameras in the conditions you describe. But why not just test it and see?
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No. What I mean is when you shoot at the HFD about 1/3 into the subject for a given lens length and aperture (or whatever exact calculation you get using charts), you expect to get "reasonable" focus 1/2 the distance in front of the HFD measured from the camera to the HFD and to infinity in back of the HFD, for each focal length and aperture--as you know. This is the "DoF" for that given camera, lens length, and aperture. Again, as you know.

So my question is within that DoF for any lens and focal length together with any aperture--and we're talking f16, not shallow DoF apertures--which camera will give the best detail in the areas in front and back of the HFD, the 5D or 1DS3?

A real word example:
You shoot a widget that is 3 feet long and 2" high at a 45 degree angle using the HFD at f16 and 35mm with X lens on both cameras at 5 feet (or whatever you need to shoot it at to maintain the widget in the DoF. Which camera will give the best detail in the DoF area, the 5D or the 1DS3?

illustration:
[a href=\"http://www.dofmaster.com/hyperfocal.html]http://www.dofmaster.com/hyperfocal.html[/url]

[Mark D Segal]

No. What I mean is when you shoot at the HFD about 1/3 into the subject for a given lens length and aperture (or whatever exact calculation you get using charts), you expect to get "reasonable" focus 1/2 the distance in front of the HFD measured from the camera to the HFD and to infinity in back of the HFD, for each focal length and aperture--as you know. This is the "DoF" for that given camera, lens length, and aperture. Again, as you know.

So my question is within that DoF for any lens and focal length together with any aperture--and we're talking f16, not shallow DoF apertures--which camera will give the best detail in the areas in front and back of the HFD, the 5D or 1DS3?

A real word example:
You shoot a widget that is 3 feet long and 2" high at a 45 degree angle using the HFD at f16 and 35mm with X lens on both cameras at 5 feet (or whatever you need to shoot it at to maintain the widget in the DoF. Which camera will give the best detail in the DoF area, the 5D or the 1DS3?

illustration:
http://www.dofmaster.com/hyperfocal.html
[a href=\"index.php?act=findpost&pid=207775\"][{POST_SNAPBACK}][/a]

OK - it's the reverse: anything relatively IN-focus. In this case I think the gist of the discussion in this thread would suggest that notwithstanding the diffraction hit at narrower apertures, the higher resolution sensor will still have an advantage in rendering fine detail.

[Ray]

Emil, I read your post but I didn't pick up on it in relation to Doug's latest question because he SEEMS (if I understood correctly) to be concerned about the resolution of out-of-focus image areas and this makes me wonder what the point is - seems to me that the resolution at which one sees these out of focus regions is hardly determinative of image quality.
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Mark,
I think the issue that Doug seems to be concerned about is the possibility that a 5D image on a certain size print might have an appearance of greater (more extensive) DoF at a particular F stop as a result of that part of the image which is in the plane of focus not being as sharp as it might be if he's used the 1Ds3 at the same F stop.

[Ray]

With regard to the sharpening I've applied, I'll reconvert my test images later with no sharpening whatsoever and re-examine the results.

I'd also like to shoot some more test images to compare noise. It's often said that larger pixels have greater dynamic range. I tend to be of the view it's the larger sensor that results in greater DR, whatever the size of the pixel.

I would expect a full frame sensor comprised of 40D pixels to have better DR than the 5D, and probably at least as good as that of the D3.

[Mark D Segal]

Mark,
I think the issue that Doug seems to be concerned about is the possibility that a 5D image on a certain size print might have an appearance of greater (more extensive) DoF at a particular F stop as a result of that part of the image which is in the plane of focus not being as sharp as it might be if he's used the 1Ds3 at the same F stop.
[a href=\"index.php?act=findpost&pid=207811\"][{POST_SNAPBACK}][/a]

Quite possibly - he'll tell us. As such, I THINK it's answered - go for the higher resolution sensor (i.e. more PPI).

[Mark D Segal]

With regard to the sharpening I've applied, I'll reconvert my test images later with no sharpening whatsoever and re-examine the results.

I'd also like to shoot some more test images to compare noise. It's often said that larger pixels have greater dynamic range. I tend to be of the view it's the larger sensor that results in greater DR, whatever the size of the pixel.

I would expect a full frame sensor comprised of 40D pixels to have better DR than the 5D, and probably at least as good as that of the D3.
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Ray - nothing I've read suggests that sensor size alone is a factor in this. It is the size and design of the photosites and the camera's firmware which affect both dynamic range and the apparent noise.

Once you've done your noise tests it would be interesting to see a comparison of your results with mine [a href=\"http://www.luminous-landscape.com/tutorials/noise.shtml]Noise About Noise[/url]

[ejmartin]

Ray - nothing I've read suggests that sensor size alone is a factor in this. It is the size and design of the photosites and the camera's firmware which affect both dynamic range and the apparent noise.

[a href=\"index.php?act=findpost&pid=207834\"][{POST_SNAPBACK}][/a]

The size of the photosites is rather uncorrelated to image level noise and DR.  If we're talking about raw data, firmware is irrelevant.  What most people tend to look at however, is pixel level noise and DR, which is of course strongly correlated to pixel size -- we have all seen how much noisier small pixels are than large ones (just look at a digicam and a DSLR at 100% pixel level view, even the 40D and 5D will show a big difference).  But when we print an image we are looking at it not at the pixel level but at the image level, and smaller pixels comprise a smaller sample of the image.  When pixels are combined, noise goes down; even when pixels are not combined, noise per unit area is largely independent of pixel size for a fixed level of sensor technology.

A fair comparison for the purposes of noise/DR, assuming pixels of a given size were tiling a full frame sensor, would be to perform a blur to a common level of absolute resolution, say 10 microns.  So for each image you want to compare, do a gaussian blur by a radius amount 10/pixel pitch in microns (40D - 5.7µ; 5D - 8.4µ; 1Ds3 - 6.4µ; 1D3 - 7.2µ; D3 - 8.45µ; D300 - 5.5µ).  Then measure the noise.  

You will find that all of these cameras do about the same, with the D3 coming out a little bit ahead; but the differences are far, far less than the differences in pixel-level noise might lead you to believe.

[joofa]

Ray - nothing I've read suggests that sensor size alone is a factor in this. It is the size and design of the photosites and the camera's firmware which affect both dynamic range and the apparent noise.

Both DR and SNR roughly increase as the square root of the pixel size. However, it not always immediately clear that what is an optimal pixel size.  A small pixel size helps in higher MTF and spatial resolution, where as a large pixel size helps in better DR and SNR.  Therefore there must exist a pixel size that strikes a compromise between high DR and SNR on the one hand, and high spatial resolution and MTF on the other. However, it is not always clear how to trade off DR and SNR with spatial resolution and MTF, and especially, how to relate these parameters to image quality.

It is possible to determine that "optimal" pixel size using certain methods that is a joint optimization of DR and SNR with MTF and spatial response. It has also been found that the "optimal" size kind of scales with technology (i.e., becomes smaller with a particular micron technology), however its rate of shrinking is slower than that of the technology. Additionally, image quality using certain measures degrades as technology scales.

[Mark D Segal]

The size of the photosites is rather uncorrelated to image level noise and DR.  If we're talking about raw data, firmware is irrelevant.  What most people tend to look at however, is pixel level noise and DR, which is of course strongly correlated to pixel size -- we have all seen how much noisier small pixels are than large ones (just look at a digicam and a DSLR at 100% pixel level view, even the 40D and 5D will show a big difference).  But when we print an image we are looking at it not at the pixel level but at the image level, and smaller pixels comprise a smaller sample of the image.  When pixels are combined, noise goes down; even when pixels are not combined, noise per unit area is largely independent of pixel size for a fixed level of sensor technology.

A fair comparison for the purposes of noise/DR, assuming pixels of a given size were tiling a full frame sensor, would be to perform a blur to a common level of absolute resolution, say 10 microns.  So for each image you want to compare, do a gaussian blur by a radius amount 10/pixel pitch in microns (40D - 5.7µ; 5D - 8.4µ; 1Ds3 - 6.4µ; 1D3 - 7.2µ; D3 - 8.45µ; D300 - 5.5µ).  Then measure the noise. 

You will find that all of these cameras do about the same, with the D3 coming out a little bit ahead; but the differences are far, far less than the differences in pixel-level noise might lead you to believe.
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Emil, if the size of the photosite is correlated to the size of the pixel and the size of the pixel is correlated with pixel level noise, then by logical inference the size of the photosite is correlated with the level of noise, ceteris paribus, is it not? The reason why I mentioned firmware is that the camera's firmware - AFAIK - does the analog to digital conversion and the manner in which that happens should have some impact on the qualities of DR and apparent noise when we open the image in Camera Raw - would it not? (i.e. please clarify what I may ne misunderstanding here.)

I don't understand your last para - "do about the same" is in regard to what? The D3 is coming out slightly ahead in respect of what? Does the last part of the statement mean that the differences in noise are far less than the differences in pixel pitch between these cameras?

Sorry for all the questions, but your message just made them come to mind!  

[Ray]

Ray - nothing I've read suggests that sensor size alone is a factor in this. It is the size and design of the photosites and the camera's firmware which affect both dynamic range and the apparent noise.

Once you've done your noise tests it would be interesting to see a comparison of your results with mine Noise About Noise
[a href=\"index.php?act=findpost&pid=207834\"][{POST_SNAPBACK}][/a]

Mark,
No, of course not. I meant 'primarily', given modern pixels and the latest technology.

Emil has explained very well what I always sensed was the case. It's the one area where the DB has an undeniable advantage over 35mm and, for the same reasons, why the Olympus 4/3rds system will probably never match the DR and low noise of FF 35mm.

Your article, "Noise about Noise", is very thorough but the crops demonstrating resolution at various F stops seem too small to show any significant differences. All I see clearly is that at f22, crops are noticeably softer than at F6.3.

Since my printer is the 24" wide Epson 7600, which I shall probably eventually upgrade to the 7880, for resolution comparisons I should perhaps use a crop enlargement that is representative of a 24"x36" print, since this is the largest print I would make from a single, unstitched image file. But this would entail comparing crops on the monitor at considerably less than 100%.

I suppose this is where the validity of pixel peeping can be questioned. It's necessary to pixel peep in order to find out if differences exist. However, having done that, it's perhaps necessary to make allowances for the significance of such differences in real-world applications, such as the making prints of a particular size.

I'll have to give this matter more thought.  

[dwdallam]

OK - it's the reverse: anything relatively IN-focus. In this case I think the gist of the discussion in this thread would suggest that notwithstanding the diffraction hit at narrower apertures, the higher resolution sensor will still have an advantage in rendering fine detail.
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Yep, that's it. It's good to know and bad at the same time. I was going to leave my 5D in the studio bolted down to a boom and take teh 1DS3 with me. Now I'll have to break it down each time I want to change from studio to location, but on the other hand, it's good to know that an 8, 000US camera will out resolve the 5D--indeed.

Thanks for those who responded, and for those discussing a similar but different topic, good luck to you also.

Unsubscribed

[Mark D Segal]

Mark,
No, of course not. I meant 'primarily', given modern pixels and the latest technology.

Emil has explained very well what I always sensed was the case. It's the one area where the DB has an undeniable advantage over 35mm and, for the same reasons, why the Olympus 4/3rds system will probably never match the DR and low noise of FF 35mm.

Your article, "Noise about Noise", is very thorough but the crops demonstrating resolution at various F stops seem too small to show any significant differences. All I see clearly is that at f22, crops are noticeably softer than at F6.3.

Since my printer is the 24" wide Epson 7600, which I shall probably eventually upgrade to the 7880, for resolution comparisons I should perhaps use a crop enlargement that is representative of a 24"x36" print, since this is the largest print I would make from a single, unstitched image file. But this would entail comparing crops on the monitor at considerably less than 100%.

I suppose this is where the validity of pixel peeping can be questioned. It's necessary to pixel peep in order to find out if differences exist. However, having done that, it's perhaps necessary to make allowances for the significance of such differences in real-world applications, such as the making prints of a particular size.

I'll have to give this matter more thought. 
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Ray, for clarity in my own mind - and I assume this is how you would see it too-  the reason why the DB is advantageous relative to FF35mm and the latter relative to 4:3 is that either or both more/larger pixels can be packed-in as the sensor gets larger - it's not the size of the sensor per se, but what it allows. Hence the interest of a previous post about optimizing the number of photosites and their size for any given sensor size.

Yes, I agree with your observation that in my article the magnification of the images is a bit small to fully appreciate the differences of apparent sharpness at the intermediate f/stops. There was a trade-off here - I didn't want to introduce more variables by resampling or over-magnifying. However, I did make prints of all those cases and the written observations are the result of two pairs of eyes examining the prints closely. Even so, until you get past f/11 the differences are really subtle even on paper.

The latest issue of PhotoshopUser magazine has an interesting article by Deke McClelland on how to make your monitor simulate how the details in an image will look when printed. It's a 10 step procedure which I haven't tried yet, but it looks like the first serious attempt (at least as far as I've seen) to softproof sharpening, which is usually considered very hard to do on a display. This may help you examining resolution as well on the display. But in the final analysis, I would still recommend actually making e.g. A4-size prints using crops at the same PPI (without resampling) as applicable for your largest print size of the full image.

Before thinking too long and hard about an Epson 7880, if you're not itching to renew your printer urgently, you may wish to wait a bit - see Michael's "What's New" for May 30th.

[ejmartin]

Emil, if the size of the photosite is correlated to the size of the pixel and the size of the pixel is correlated with pixel level noise, then by logical inference the size of the photosite is correlated with the level of noise, ceteris paribus, is it not? The reason why I mentioned firmware is that the camera's firmware - AFAIK - does the analog to digital conversion and the manner in which that happens should have some impact on the qualities of DR and apparent noise when we open the image in Camera Raw - would it not? (i.e. please clarify what I may ne misunderstanding here.)

I don't understand your last para - "do about the same" is in regard to what? The D3 is coming out slightly ahead in respect of what? Does the last part of the statement mean that the differences in noise are far less than the differences in pixel pitch between these cameras?

[a href=\"index.php?act=findpost&pid=207940\"][{POST_SNAPBACK}][/a]

The size of the photosite is correlated with the *pixel* level noise, what you see when you view the image at 100% on a monitor.  Noise has a scale dependence.  Suppose we combine the output of a 2x2 block of photosites.  The signal is additive -- one just adds the photon counts from all four.  Noise adds as RMS -- the sqrt of the sum of the squares of the pixel noises.  This means if all are about the same, signal goes up by four, but the noise only goes up by two, and so the S/N ratio improves if we halve the resolution.  

It is easy to see this for yourself.  Open a new canvas in photoshop, fill it with middle gray and add a bunch of gaussian noise (Filter>Noise>Add Noise).  Now go to the Gaussian blur filter and watch what happens to the width of the histogram as you change the radius of the blur.  Increasing the blur radius decreases the image resolution; it also decreases the noise.

So if you properly resample say a 1Ds3 image to the resolution of a D3, the apparent one stop pixel level noise advantage of the D3 drops to something on the order of 20%.  That 20% can be understood from the fact that the D3 is 20% more efficient per unit area at collecting photons than the 1Ds3.  So the 1Ds3 has higher *pixel* level noise, but *image* level noise -- noise measured at the same spatial scale -- is not all that different.  Now, that near equivalence is there whether we resample/blur the 1Ds3 image or not, since the same photons were collected by the sensor whether we bin the pixel samples together or not.  Since noise goes as sqrt of signal, that 20% difference in photons is only about a 10% difference in noise amplitude to the 1Ds3's detriment; on the other side of the balance sheet is a 32% increase in linear resolution.

It is thus important when comparing noise figures to compare them at the same scale; any pixel level noise measurement should be divided by the square root of the MP count to normalize relative to a consistent and comparable percentage of the frame size.  If one wants to extrapolate -- eg imagine how a full frame sensor tiled with 40D pixels would perform -- one should multiply the pixel level noise of the cameras to be compared by the respective pixel pitches.  By this measure, the 40D, 1Ds3, and 1D3 have about the same noise at comparable scales, even though their pixel level noises are quite different (and larger the smaller the photosite is).  One way to understand this is that Canon did their job right, and all three sensors are capturing the same number of photons per unit area.  BTW, some people have speculated that the reason the D3 does about 20% better is that its microlenses purportedly have about 20% better area coverage.

As for analog-to-digital conversion, that is done in hardware, not firmware; the only way that firmware could have an effect is if the camera is doing some processing of the sensor data before it is written to raw (eg noise reduction), and I have seen no evidence of that under ordinary shooting conditions (not at all in Canons with default settings; Nikon does some NR on raw for exposures of 1/4 sec and longer but not otherwise).

The reason MFDB's do so well is that they have twice the sensor area of 35mm, so gather more photons; the size of individual pixels matters little in this regard.

Sorry for the lengthy diatribe...

[Ray]

Before thinking too long and hard about an Epson 7880, if you're not itching to renew your printer urgently, you may wish to wait a bit - see Michael's "What's New" for May 30th.

Mark,
I meant the 7990 due in Australia around October this year; the one with reduced ink costs, more cartridges and easy swapping between Photo Black and Matte Black.

This could be an expensive year with the 5D upgrade and/or Sony A900 out soon; another trip to Nepal, Thailand and Cambodia to test my new camera; and a new printer with increased color gamut, reduced bronzing and easy changing from gloss paper to matte.

I really think that Canon should release a 26mp 5D upgrade in order to trump Sony's offering of a 24mp DSLR, although I guess owners of a 1Ds3 might feel a bit peeved if Canon were to do that.  

Ray, for clarity in my own mind - and I assume this is how you would see it too-  the reason why the DB is advantageous relative to FF35mm and the latter relative to 4:3 is that either or both more/larger pixels can be packed-in as the sensor gets larger - it's not the size of the sensor per se, but what it allows. Hence the interest of a previous post about optimizing the number of photosites and their size for any given sensor size.

I wonder if this is just semantics. I prefer to see it from the perspective of the composition being photographed. It has a specific FoV and DoF. At a given ISO the sensor will receive an amount of light in proportion to its size, assuming correct exposure. The greater amount of light that the larger sensor requires for proper exposure ensures greater DR, irrespective of pixel size, but not of course irrespective of pixel quality and factors such as quantum efficiency.

The latest issue of PhotoshopUser magazine has an interesting article by Deke McClelland on how to make your monitor simulate how the details in an image will look when printed. It's a 10 step procedure which I haven't tried yet, but it looks like the first serious attempt (at least as far as I've seen) to softproof sharpening, which is usually considered very hard to do on a display. This may help you examining resolution as well on the display. But in the final analysis, I would still recommend actually making e.g. A4-size prints using crops at the same PPI (without resampling) as applicable for your largest print size of the full image.

Thanks. I'll look into that.

[Josh-H]

The size of the photosite is correlated with the *pixel* level noise, what you see when you view the image at 100% on a monitor.  Noise has a scale dependence.  Suppose we combine the output of a 2x2 block of photosites.  The signal is additive -- one just adds the photon counts from all four.  Noise adds as RMS -- the sqrt of the sum of the squares of the pixel noises.  This means if all are about the same, signal goes up by four, but the noise only goes up by two, and so the S/N ratio improves if we halve the resolution. 

It is easy to see this for yourself.  Open a new canvas in photoshop, fill it with middle gray and add a bunch of gaussian noise (Filter>Noise>Add Noise).  Now go to the Gaussian blur filter and watch what happens to the width of the histogram as you change the radius of the blur.  Increasing the blur radius decreases the image resolution; it also decreases the noise.

So if you properly resample say a 1Ds3 image to the resolution of a D3, the apparent one stop pixel level noise advantage of the D3 drops to something on the order of 20%.  That 20% can be understood from the fact that the D3 is 20% more efficient per unit area at collecting photons than the 1Ds3.  So the 1Ds3 has higher *pixel* level noise, but *image* level noise -- noise measured at the same spatial scale -- is not all that different.  Now, that near equivalence is there whether we resample/blur the 1Ds3 image or not, since the same photons were collected by the sensor whether we bin the pixel samples together or not.  Since noise goes as sqrt of signal, that 20% difference in photons is only about a 10% difference in noise amplitude to the 1Ds3's detriment; on the other side of the balance sheet is a 32% increase in linear resolution.

It is thus important when comparing noise figures to compare them at the same scale; any pixel level noise measurement should be divided by the square root of the MP count to normalize relative to a consistent and comparable percentage of the frame size.  If one wants to extrapolate -- eg imagine how a full frame sensor tiled with 40D pixels would perform -- one should multiply the pixel level noise of the cameras to be compared by the respective pixel pitches.  By this measure, the 40D, 1Ds3, and 1D3 have about the same noise at comparable scales, even though their pixel level noises are quite different (and larger the smaller the photosite is).  One way to understand this is that Canon did their job right, and all three sensors are capturing the same number of photons per unit area.  BTW, some people have speculated that the reason the D3 does about 20% better is that its microlenses purportedly have about 20% better area coverage.

As for analog-to-digital conversion, that is done in hardware, not firmware; the only way that firmware could have an effect is if the camera is doing some processing of the sensor data before it is written to raw (eg noise reduction), and I have seen no evidence of that under ordinary shooting conditions (not at all in Canons with default settings; Nikon does some NR on raw for exposures of 1/4 sec and longer but not otherwise).

The reason MFDB's do so well is that they have twice the sensor area of 35mm, so gather more photons; the size of individual pixels matters little in this regard.

Sorry for the lengthy diatribe...
[a href=\"index.php?act=findpost&pid=207996\"][{POST_SNAPBACK}][/a]

Dont apologise- that was an excellent and easy to understand explanation.

Thanks for posting.

[Mark D Segal]

The size of the photosite is correlated with the *pixel* level noise, what you see when you view the image at 100% on a monitor.  Noise has a scale dependence.  ..................

[a href=\"index.php?act=findpost&pid=207996\"][{POST_SNAPBACK}][/a]

Thanks Emil - this is a post to keep in one's archives. Very useful.

[Mark D Segal]

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

The greater amount of light that the larger sensor requires for proper exposure ensures greater DR, irrespective of pixel size, ...................................

[a href=\"index.php?act=findpost&pid=208000\"][{POST_SNAPBACK}][/a]

I don't profess any expertise on the subject of how photosites register the tonal range of a scene, but this does not come across as intuitively correct to me. I would like to be educated on that point.

[Ray]

I don't profess any expertise on the subject of how photosites register the tonal range of a scene...............[a href=\"index.php?act=findpost&pid=208044\"][{POST_SNAPBACK}][/a]

Nor do I, yet it does seem intuitive to me that a larger sensor requires more light than a smaller sensor requires, in order to record the same scene. If you stitch together two 1Ds3 sensors, you need double the amount of light to fully expose that doubled sensor area, and as a consequence DR is increased by approximately one stop.

In fact Mark, it seems to me that this increase in DR would apply whatever the initial sensor size. Double the area of a 5D sensor and presumably you'd still get approximately one stop increase in DR. Double the area of a G9 or Olympus E3 sensor and you'd expect to get the same increase in DR despite the fact that the pixels are a different size in each case.