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Author Topic: Canon 50D @ 15MP  (Read 114106 times)

semillerimages

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Canon 50D @ 15MP
« Reply #80 on: August 27, 2008, 11:55:17 pm »

These threads are always so hilarious - new camera comes out, pontification begins, hot air is exhaled, and then the same friggen arguments ensue about image quality again and again and again.
I look forward with a smile to see these because I always get a laugh, so thank you all for arguing about absolutely meaningless nonsense

*steve
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Tony Beach

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Canon 50D @ 15MP
« Reply #81 on: August 28, 2008, 12:05:11 am »

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thank you all for arguing about absolutely meaningless nonsense [a href=\"index.php?act=findpost&pid=217718\"][{POST_SNAPBACK}][/a]

You're welcome.  Thank you for your equally meaningless contribution.
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Panopeeper

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Canon 50D @ 15MP
« Reply #82 on: August 28, 2008, 12:13:07 am »

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I look forward with a smile to see these because I always get a laugh, so thank you all for arguing about absolutely meaningless nonsense
I look forward with a laugh to see the digitally challanged to whine about posts they don't understand a word of.
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Gabor

kers

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Canon 50D @ 15MP
« Reply #83 on: August 28, 2008, 07:38:38 am »

coming from a 12 mp Nikon d2x and now using the Nikon 12mp Nikon D3 the quality of my photographs have been much improved. It had a lot to do with lens quality more than with the body.

I work a lot with extreme wide angle.
 The improvement is that now I have good lenses at last that are sharp corner to corner at d8 ( 14-24mm nikkor 2,8)

In the Dx format there was nothing to buy in this class. The Nikkor 12-24mm  d4 was just as bad as the sigma & other offerings- Carl zeiss only came up with a very good 25mm lens. ( Only now they have the 18mm)

I don't know how the Canpn wide angles are but to address the 15mp i guess you need the 2200$ 14mm 2,8 lens
« Last Edit: August 28, 2008, 07:39:51 am by kers »
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NLund

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Canon 50D @ 15MP
« Reply #84 on: August 28, 2008, 01:01:39 pm »

I agree with Semillarimages. Post 81.

There is a lot of good technical information in this thread, but the bashing is tiresome.

I want to get excited for new cameras, not argue interpretations, physics, semantics, and egos.

--

I have a 30D I've been using for three years now. I'm planning on upgrading to the 5d mk II and hoping that it's a great camera.

If it has the same pixel pitch as the 50D, how many megapixels would it be?
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fike

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Canon 50D @ 15MP
« Reply #85 on: August 28, 2008, 01:30:21 pm »

I also grow weary of endless speculation about a camera that we haven't yet seen.  I don't consider myself a pixel-peeper, but I have been known to test my lenses at multiple apertures and focal lengths to find the sweet spot.  I have read this discussion from beginning to end. I have learned more about diffraction than I knew before.  BUT...

There are a three main areas that I think this discussion cavalierly misses.

One:  All of these discussions are predicated on extrapolating theoretical limits based upon the previous generations of technology.  We should not assume that this sensor and the camera that goes around it will be limited by all the same factors that the previous generation was.  Unless you can independently test a lens without a sensor, or film, then we must wait to see how it performs on the new sensor.  This is a classic mistake of scientists....changing too many variables and then trying to make conclusions based upon assumptions and theories.  

This leads me to the second area.

Two:  Unknown properties of sensor. This new sensor can easily have different thermal or electrical properties that would decrease the effect of noise.  When silicon technology advances to a new process node (I don't even know if they have moved to a new node) typically, the gates and circuits become smaller.  This means that it takes less voltage to power the device (unless they have increased the processor speed too, as is general the case with CPUs).  With a decrease in voltage and power, there is a proportional decrease in temperature and noise.  I am not saying this is the case with the 50D.  What I am saying is that there is a great deal that can be done on chip to change the game--change the performance of the sensor.

This leads me to my final point.

Three: In-camera digital processing. With improved DIGIC processors (more processing power) the images can have more substantial filters and can be processed more quickly.  I know I am not alone when I relate my first experience of digital image enhancement, when I moved that levels slider bar and suddenly saw details in the shadows that I never knew were there.  Detail that was not originally visible suddenly appeared--as if by magic.  Similarly, In-camera digital processing could squeeze out a bit more resolution than we previously thought possible.  In camera sharpening algorithms that could account for predictable diffraction effects could easily be imagined.  Further, Canon, with their detailed knowledge of the sensor's attributes, should be able to create highly effective processing algorithms.

So, this is why I will wait for the camera before I declare it a non-starter that is diffraction limited beyond f/8 (I love f/8, it is my favorite aperture).  When the camera comes out, I will closely study the sample photos, and I might even look at some MTF charts.
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Tony Beach

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Canon 50D @ 15MP
« Reply #86 on: August 28, 2008, 01:57:21 pm »

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So, this is why I will wait for the camera before I declare it a non-starter that is diffraction limited beyond f/8 (I love f/8, it is my favorite aperture).  When the camera comes out, I will closely study the sample photos, and I might even look at some MTF charts.
[a href=\"index.php?act=findpost&pid=217869\"][{POST_SNAPBACK}][/a]

I think my point is repeatedly missed.  It's not that the 50D becomes worse than the 40d or 30D beyond f/8, my point is that its resolution advantages quickly diminish to indistinguishable and all you have are bigger files.  It is not my intention to rain on anyone's parade and it was merely a point I raised in passing that has been repeatedly challenged and now is condemned as "bashing".  If someone thinks they can buy this new camera and by virtue of its 15 MP resolution set their lens to f/16 and get better images than they were getting from their 30D, well they will be disappointed.

Frankly, I'm unimpressed with discussions about the putative image quality (both pro and con) of a camera no one here has yet handled -- and I find most sample photos dubious (especially those claiming to demonstrate a camera's weaknesses), there are a lot of photographers who are too quick to blame their gear rather than their technical shortcomings.
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Pete Ferling

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Canon 50D @ 15MP
« Reply #87 on: August 28, 2008, 04:13:46 pm »

Tony, Canon may have pushed the envelope by making smaller photosites and the gapless microlens, and all we can do is wait for real results. If having more mega pixels on the same size sensor alone only produces more defraction, then such results will prove to be a nonsense marketing gimmick, and make me a happier 40D owner.

I can tell you in the studio when I'm pushing my 40D to the limit, that I have run into the defraction wall at F18 (where it gets noticed), that was easily fixed by placing the same lens onto my old 1Ds (mark 1), with full frame sensor and larger sites.

So, I think a 5d mk ii (if and when it's announced) would still of interest to me over a 50d, and this speculation is just too hard to avoid in months ahead that we have to wait.


This site, if not mentioned before, might be of interest:

http://diglloyd.com/diglloyd/free/Diffraction/index.html
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kvanlear

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Canon 50D @ 15MP
« Reply #88 on: August 28, 2008, 04:28:30 pm »

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15MP on an APS-C sensor?  Isn't that overkill?  Didn't Canon learn their lesson with the 1DSMK3?

My guess is as long as the manufacturers can convince the lemmings they need more megapixels, they'll continue down this silly path, while real improvements will trickle in slowly.

Don't forget about us landscape photographers.  We always need as many mp as we can get.  Not that I'm implying the 50D is the ultimate landscape lens.  However others in the line have and will have more mp and this is not unwelcome for landscape shooting.  It's also good for wildlife shooting when one has to crop a tiny subject out of a large picture and we want to maintain enough resolution to make a decent print.

I am not one who wants to invest in a MF system to get those high-end results due to the size and weight of those systems and the cost.  The closer 35mm gets to those resolutions the happier I am.  I'm sure portrait and wedding photographers don't care because they have the resolution they need already.  Just remember that there are plenty of segments of photography where higher resolution is welcome.
« Last Edit: August 28, 2008, 05:08:29 pm by kvanlear »
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kvanlear

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« Reply #89 on: August 28, 2008, 04:34:36 pm »

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For landscape photography the increased MP will be useless.  Stop down to f/11 and compare a 50D file to a 40D file; in terms of resolution there will be no difference.
[a href=\"index.php?act=findpost&pid=217312\"][{POST_SNAPBACK}][/a]

Oh, you have a 50D then?  C'mon, the f/stop only increases the DOF, it's not going to put more pixels in the image.  The 50D file will be bigger and have finer detail.
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fike

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Canon 50D @ 15MP
« Reply #90 on: August 28, 2008, 04:44:53 pm »

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Oh, you have a 50D then?  C'mon, the f/stop only increases the DOF, it's not going to put more pixels in the image.  The 50D file will be bigger and have finer detail.
[a href=\"index.php?act=findpost&pid=217919\"][{POST_SNAPBACK}][/a]

You should go back and read the long thread.  Tony's point is well explained and possibly accurate for the 50D.

What is left to be determined is whether canon's 50D has made some innovation that compensates for diffraction.
« Last Edit: August 28, 2008, 04:45:24 pm by fike »
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DiaAzul

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Canon 50D @ 15MP
« Reply #91 on: August 28, 2008, 04:52:37 pm »

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I think my point is repeatedly missed.  It's not that the 50D becomes worse than the 40d or 30D beyond f/8, my point is that its resolution advantages quickly diminish to indistinguishable and all you have are bigger files. 
[a href=\"index.php?act=findpost&pid=217880\"][{POST_SNAPBACK}][/a]

Perhaps the end game with a 50Mpixel sensor with lenses/apertures that cannot resolve more than a 12Mpixel sensor is to increase the range of pixel colours that are used to detect the image to increase colour gamut. So, instead of RGB we could get CMYK or RGB plus Yellow and Magenta pixels. There is no rule that the sensor should remain a Beyer RGB pattern with 2 Green 1 Red 1 Blue in a square grid. There may be other reasons to move from traditional layouts, e.g. variable size pixels (large/ small) to provide greater dynamic range or specific layouts to facilitate pixel binning.

Even if the spatial resolution is limited by the lens there may be good reason to use the new techniques in innovative ways to drive other enhancements in overall performance.
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kvanlear

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Canon 50D @ 15MP
« Reply #92 on: August 28, 2008, 05:07:49 pm »

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You should go back and read the long thread.  Tony's point is well explained and possibly accurate for the 50D.

What is left to be determined is whether canon's 50D has made some innovation that compensates for diffraction.
[a href=\"index.php?act=findpost&pid=217921\"][{POST_SNAPBACK}][/a]

I did and I'm not fully convinced that diffraction is going to be as big a issue as postulated.  The fact is that the camera isn't out yet and no one really knows how those gapless microlenses are going to affect diffraction one way or the other - well, the Canon engineers almost certainly know, but they aren't talking about it.  We are all also aware that different lenses have different diffraction characteristics.  If Tony turns out to be right then T/S lenses are always there of course to save us from diffraction on product shots and landscape shots, as an aside we could use some more those T/S lenses.  I confess that I'm not going to buy the 50D for landscape work myself because I am aware that diffraction does come quicker on APS-C.  I'll be getting the new FF for those shots.
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bjanes

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« Reply #93 on: August 28, 2008, 06:20:38 pm »

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I did and I'm not fully convinced that diffraction is going to be as big a issue as postulated.  The fact is that the camera isn't out yet and no one really knows how those gapless microlenses are going to affect diffraction one way or the other - well, the Canon engineers almost certainly know, but they aren't talking about it.
[a href=\"index.php?act=findpost&pid=217928\"][{POST_SNAPBACK}][/a]

Gaples microlenses will help improve light collecting ability of the pixels, but diffraction is determined mainly by the pixel spacing, which is not affected by the gapless lenses.

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We are all also aware that different lenses have different diffraction characteristics.  If Tony turns out to be right then T/S lenses are always there of course to save us from diffraction on product shots and landscape shots, as an aside we could use some more those T/S lenses.
[a href=\"index.php?act=findpost&pid=217928\"][{POST_SNAPBACK}][/a]

Theoretically, diffraction is determined solely by the aperture (f/stop). The type of lens should have little to do with diffraction as long as the f/stop is the same. We often read in lens reviews that a particular lens performs well down to a certain aperture, but beyond that diffraction sets in quickly and performance falls off. That should be true for any lens, but perhaps there are some differences that I am not aware of.


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I confess that I'm not going to buy the 50D for landscape work myself because I am aware that diffraction does come quicker on APS-C.  I'll be getting the new FF for those shots.
[a href=\"index.php?act=findpost&pid=217928\"][{POST_SNAPBACK}][/a]

Diffraction does come quicker on APS-C, but this is partially offset by less need to stop down for equivalent depth of field. Even though the 50D becomes diffraction limited at a larger aperture than a 10 MP APS camera, the image quality at f/16 will be no worse with the 50D than the 40D. If you have a good lens and can use a larger aperture, you have the option of getting better IQ with the 50D. Lenses with tilts and shifts can help with depth of field as you point out, and you can also use image stacking to improve depth of field.

If you want to use panorama techniques for landscape work, say combining three or four shots in portrait mode to make a final picture in landscape format, you can get very high resolution pictures. Some photographers prefer APS cameras for this purpose since you are using the central portion of the image with the best quality. If you need 4 by 5 quality, you can use multirow techniques.

I have the Nikon D3, which trades resolution for light gathering ability (the opposite approach to the 50D), but there trade offs and which approach is best depends on your needs. Digital workflow is very flexible, and one can often work around many of the limitations of one's camera. The D3 is good for sports and photojournalism, but the 1Ds3 would be better for landscape.

Bill
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Ray

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Canon 50D @ 15MP
« Reply #94 on: August 28, 2008, 08:47:12 pm »

Discussions like these serve the purpose of raising awareness of the issues involved. I'm surprised that anyone should object to them.

On the other hand, perhaps I can understand why, when one poster (whom I shall not name), after objecting to the discussion, goes on to ask how many pixels would a full frame sensor have if its pixel pitch were that of the 50D, thus demonstrating that he is either mathematically challenged, or is unaware of the size difference between the Canon cropped format and FF 35mm.

I get the impression from some of the posts in this thread that some posters believe there is a connection between pixel pitch and diffraction and that high density sensors are somehow causing diffraction.

Perhaps it's just the way they are expressing themselves, so let's be clear about this. Diffraction is a property of the lens, not of the sensor. Don't blame the sensor for the limitations of the laws of physics with regard to optics.

The P45 has approximately the same pixel pitch as a 20D. Because the sensor is double the size of 35mm, one needs to stop down about one stop more than one would with a 35mm system to get the same DoF as FF 35mm, and 2 1/2 stops more to get the same DoF as the 50D. You don't hear P45 owners whingeing about their small pixel pitch, do you?

Be grateful for what's being offered. There is already a lot of research taking place in nanotechnology with regard to the production of artificial materials with a negative refractive index. If it ever becomes possible to use such materials in camera lenses, you might be able to record sharp images at F32 with a future 50mp APS-C sensor   .
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Panopeeper

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« Reply #95 on: August 28, 2008, 10:02:13 pm »

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The P45 has approximately the same pixel pitch as a 20D. Because the sensor is double the size of 35mm, one needs to stop down about one stop more than one would with a 35mm system to get the same DoF as FF 35mm, and 2 1/2 stops more to get the same DoF as the 50D
It is still a nonsense.

The depth of field has NOTHING to do with the sensor size. It's a simple thing (how did you express this? except for the mathematically challenged?).
« Last Edit: August 28, 2008, 10:43:58 pm by Panopeeper »
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Gabor

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« Reply #96 on: August 28, 2008, 10:49:26 pm »

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It is still a nonsense.

The depth of field has NOTHING to do with the sensor size. It's a simple thing (how did you express this? except for the mathematically challenged?).
[a href=\"index.php?act=findpost&pid=217988\"][{POST_SNAPBACK}][/a]

Once again, Gabor, you have forgotten that my concern is with the woods. Your concern appears to be only with the trees within the woods.

Without regard to such factors as composition and FoV, you are perfectly correct that DoF has nothing to do with sensor size. But my compositions and images have a lot to do with sensor size. The sensor size influences my choice of focal length and the perspective from which I take the shot, and that in turn influences DoF.

I'm surprised you find such ideas nonsense. It's pretty basic to me. I'm dealing with such issues all the time.

Edit: For the sake of clarity, I should elaborate on what is probably a source of much confusion. I have assumed in my comments that most users of DSLRs wish to maximise the real estate of their sensors. The people contributing to this thread are obviously concerned about resolution. If you are concerned about resolution, you don't use a 50mm lens and then crop the resulting image to the same field-of-view you would have got using an 80mm lens from the same position. You try to use an 80mm lens, even if it's a zoom of lower quality than the 50mm prime.

If two photographers are standing next to each other, one with a 20D and 50mm lens, and the other with a 1Ds3 and 50mm lens, and they shoot the same scene using the same F stop, then the parts that both images have in common, will, of course, be very similar in terms of both resolution and DoF, but the compositions will be very different.

Most photographers carry a range of lenses or a zoom with a range of focal lengths. People who claim that DoF has nothing to do with sensor size are being very disingenuous.
« Last Edit: August 28, 2008, 11:27:44 pm by Ray »
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Tony Beach

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Canon 50D @ 15MP
« Reply #97 on: August 29, 2008, 12:23:24 am »

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I get the impression from some of the posts in this thread that some posters believe there is a connection between pixel pitch and diffraction and that high density sensors are somehow causing diffraction.

Perhaps it's just the way they are expressing themselves, so let's be clear about this. Diffraction is a property of the lens, not of the sensor. Don't blame the sensor for the limitations of the laws of physics with regard to optics.[a href=\"index.php?act=findpost&pid=217977\"][{POST_SNAPBACK}][/a]

I resemble that remark.  I know I'm beating a dead horse here, but feel compelled to keep it up because some think the horse is merely sleeping.  The point isn't that the photosites are "causing" the diffraction, it's that that the close proximity of the photosites to one another is recording the diffraction; and the closer together they are the sooner they record that diffraction.  

Did you read and fully comprehend the article I have already twice linked to in this thread?  Have you performed any tests to prove or disprove what I'm asserting?  I'm shocked, shocked that no one here doesn't have a couple of cameras (say a D300 and a D700), a good lens, a resolution target, a solid tripod and remote shutter release, and the patience and curiosity to test this theory for themselves and then present their results.
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Panopeeper

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« Reply #98 on: August 29, 2008, 12:51:49 am »

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Diffraction is a property of the lens, not of the sensor
That's right. However, the diffraction effect is a function of the diffraction and of the circle of confusion, which depends on the pixel size.
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Gabor

ejmartin

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« Reply #99 on: August 29, 2008, 01:05:43 am »

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I resemble that remark.  I know I'm beating a dead horse here, but feel compelled to keep it up because some think the horse is merely sleeping.  The point isn't that the photosites are "causing" the diffraction, it's that that the close proximity of the photosites to one another is recording the diffraction; and the closer together they are the sooner they record that diffraction. 

Did you read and fully comprehend the article I have already twice linked to in this thread?  Have you performed any tests to prove or disprove what I'm asserting?  I'm shocked, shocked that no one here doesn't have a couple of cameras (say a D300 and a D700), a good lens, a resolution target, a solid tripod and remote shutter release, and the patience and curiosity to test this theory for themselves and then present their results.
[{POST_SNAPBACK}][/a]


First, why is a problem if the sensor is recording diffraction?  When the sensor is not recording diffraction, then the limiting factor in resolution is the pixel pitch of the sensor, and that means that resolution offered by the lens is being left on the table by the shortcomings of the sensor.  At least one can be assured that if the sensor is showing diffractions effects, that it is not a source of lost detail in the image.  A coarser pixel pitch never provides more resolution, it simply throws away resolution in a wider variety of circumstances where a finer pixel pitch could deliver it.

Second, while I myself have not performed tests, I have analyzed those performed by DPReview, which has tested the Nikon and Canon 70-200/2.8 on both FF (D3 and 5D respectively) as well as APS-C (D300 and 40D respectively).  I reported on that analysis in a variety of fora:

[a href=\"http://forums.dpreview.com/forums/read.asp?forum=1021&message=28590555]http://forums.dpreview.com/forums/read.asp...essage=28590555[/url]

http://www.naturescapes.net/phpBB3/viewtop...397195#p1397195

The bottom line is that smaller pixels provide more resolution in both of these examples, even when the optics is diffraction limited.  Now granted, this resolution is based on slanted edge tests and may not always be realized in practice as actual line pair resolution in the diffraction limited regime; but certainly the finer pixel pitch sensor will never do worse than the coarser one under any circumstance.

The obsession with diffraction effects at small apertures ignores the substantial resolution benefit to be gained when shooting at wider apertures with a finer pixel pitch.  A finer pixel pitch does no worse at small apertures, and substantially better at wide apertures.  And so all the moaning about "diffraction limitation" of finer pixel pitch seems to me misplaced.
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