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Author Topic: "Nikon D800 / D800E First Comparison"  (Read 39763 times)
Ray
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« Reply #40 on: April 19, 2012, 08:57:55 PM »
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I wasn't clear on whether the second set of comparisons was done with identical sharpening or not. But to me it looks like the 800 file could handle more sharpening, especially for printing.

Consider the noise implications of greater sharpening.
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Guillermo Luijk
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« Reply #41 on: April 19, 2012, 09:33:17 PM »
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The question for me is whether the 800e would be sharper if files from both cameras were sharpened to their maximum potential, especially using deconvolution. The 800e files probably can take less sharpening before showing artifacts.

Regarding this, I think it's important to distinguish between capture sharpness (accutance), and real detail (information). Sampling theory says that no detail is lost if an ideal AA filter is used followed by ideal impulse sampling. The differences in real detail (not in capture sharpness) between the D800 and D800E should be explained through the non-ideal AA filter of the D800.

Just for demostrative purposes, using Photoshop I resampled down to 256x256 a 2048x2048 image with repetitive patterns prone to aliasing/moiré (see accordion) using different AA filters, from no AA filter to 4px gaussian blur, followed by ideal sampling (decimation):

No aliasing in the original file:



Rescaling down in Photoshop with different AA filters:



Aliasing artifacts are clear in all images, being the one with 4px AA filtering the first one acceptable IMO. In the non problematic areas (head and clothes of the musician), the 4px image is less sharp. But does it contain less useful information than the aliased images?.

After sharpening it (centre), I doubt there is really any extra information in the other images, which where still a bit sharper but displayed aliasing artifacts (see accordion and metallic tubes of the chair in the 2px version):




Translating this into the D800 vs D800E debate, what is a better choice: more protection against aliasing/moiré at the expense of some (recoverable?) loss of sharpness? or extra sharpness (without additional useful information?) at the expense of more aliasing/moiré artifacts in particular scenes?.

Regards


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ErikKaffehr
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« Reply #42 on: April 19, 2012, 11:08:07 PM »
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Thanks a lot!

Erik

Thanks in advance. The results will be interesting.

Regards,

Bill
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ErikKaffehr
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« Reply #43 on: April 19, 2012, 11:22:10 PM »
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Hi,

I played around a bit with sharpening on a screen dump of Michael's image.

The screen dump shows the duplicates:

1) Original image
2) Right hand image sharpened
3) Both images sharpened by the same amount

That was quite extensive sharpening and it of course much affected by JPEG artifacts.

Normally I would use the enclosed settings for low ISO landscape images in Lightroom. May be a bit excessive but I like them.

Best regards
Erik

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hjulenissen
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« Reply #44 on: April 20, 2012, 03:14:59 AM »
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Regarding this, I think it's important to distinguish between capture sharpness (accutance), and real detail (information). Sampling theory says that no detail is lost if an ideal AA filter is used followed by ideal impulse sampling. The differences in real detail (not in capture sharpness) between the D800 and D800E should be explained through the non-ideal AA filter of the D800.
From the simplified frequency-domain theoretical dsp POV, a sin(x)/x function might appear perfect, as it has a perfectly flat, wide passband (true detail), and perfect attenuation of the stop-band (no aliasing). In practice, this could lead to ringing and other artifacts around sharp edges.

The "ideal" linear optical prefilter would probably be close to the kernels preferred for image downsampling. I think that lanczos (windowed sin(x)/x) is close to what most seem to prefer. But an optical aa filter could not have "negative light" contributions, so it might ideally be closer to a gaussian or whatever.

Practice tells us that photographers tend to be less concerned with what is "real" detail, and more concerned with what "gives an impressive popping 3d print". Even if the D800 had the best conceivable OLPF (which it does not) in terms of sampling theory, some users might prefer the aliasing bound to be present in the D800E. I think it is a good thing that Nikon gave users the choice.

-h
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MarkL
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« Reply #45 on: April 20, 2012, 04:55:28 AM »
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I have been eagerly awaiting comparisons like these trying to make a decision, after nikon's samples I was surprised to see just how much more detail there with in the E file. What would be interesting is at what apertures of the 85mm this difference remains evident so see how useful it will be in the real world, if it's a wash by f/11 or at f/2.8 the usefulness is limited somewhat.
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BartvanderWolf
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« Reply #46 on: April 20, 2012, 05:17:30 AM »
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Consider the noise implications of greater sharpening.

Proper sharpening does not have to increase the overall noise to unacceptable levels. Featureless areas can/should be masked, and areas with many details already have a favorable signal to noise ratio.

On top of that, algorithms like an adaptive Richardson-Lucy restoration will already dampen the noise and increase the S/N ratio with each iteration. One can try RawTherapee to see how far one can push the sharpening before noise becomes a problem (which it rarely is with printing).

Cheers,
Bart
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Ray
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« Reply #47 on: April 20, 2012, 07:11:09 AM »
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Proper sharpening does not have to increase the overall noise to unacceptable levels.

Well, I guess that's self-evident, Bart. If the sharpening were to increase noise to unacceptable levels, it couldn't be considered proper. Grin

What occurs to me is, if the D800 shot is always sharpened so that it looks as sharp as the D800E shot, could there be visibly more noise at least somewhere in the full size image, despite one's best efforts.

It may well be the case that at base ISO this is less likely to be a problem. But what about ISO 3200? What about small crops that one wants to print largish?


Quote
Featureless areas can/should be masked, and areas with many details already have a favorable signal to noise ratio.

I agree that featureless areas can be masked, but detail in the deep shadows tends to have an unfavourable SNR. When I use Smart Sharpen, I usually fade the amount of sharpening applied to the shadows.

I also wonder what will happen at high ISO when noise may be a problem without any sharpening at all.

Quote
On top of that, algorithms like an adaptive Richardson-Lucy restoration will already dampen the noise and increase the S/N ratio with each iteration. One can try RawTherapee to see how far one can push the sharpening before noise becomes a problem (which it rarely is with printing).

Maybe, but I don't have the cameras to try that. I have to make a decision as to which model to order. I'm currently favouring the D800E.

I was very impressed with Focus Magic, but I'm disappointed they are taking so long to develop a version compatible with 64 bit Windows OS.

Cheers!

Ray

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johan
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« Reply #48 on: April 20, 2012, 03:29:47 PM »
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I find it very surprising that Michael says that he can see the difference between the two Nikon c
ameras in prints. Not long ago he posted a story comparing prints from a Canon G12 and a Hasselblad saying most of his photographer friends could not tell the cameras apart; in prints.
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Ray
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« Reply #49 on: April 20, 2012, 08:26:26 PM »
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I find it very surprising that Michael says that he can see the difference between the two Nikon c
ameras in prints. Not long ago he posted a story comparing prints from a Canon G12 and a Hasselblad saying most of his photographer friends could not tell the cameras apart; in prints.


The situations are quite different. In the case of the G12/P45 comparison, the MF lens was not used at its sharpest aperture whereas the G12 probably was. (From memory, I think it was F3.5 compared with F11).

Secondly, the print size of A3+ would have resulted in most of the resolution benefits of the P45 being thrown away in downsampling, whereas A3+ size is just about right for the G12 without any interpolation of pixels.

The 36.3mp of the D800 is good for a 20"x30" print without interpolation (depending on choice of 240ppi or 300ppi), and that is the size, or larger, one would compare detail and resolution. In practice, people frequently interpolate images to make large prints. I've made 24"x36" prints from my 12mp Canon 5D, which look acceptably sharp from a reasonably close distance, like a viewing distance equal to the diagonal of the print. But I sure wish I'd had a D800E at the time I took those shots.
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Ray
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« Reply #50 on: April 21, 2012, 06:03:15 PM »
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Having examined Michael's second, updated comparison of shots of a $20 bill after both have been sharpened, I'm beginning to think the resolution differences between the D800 and the D800E really are too small to be worth bothering about.

The differences in the unsharpened images are sufficiently great to become a concern, but appropriate sharpening seems to have narrowed the differences to a point where one really wonders under what circumstances, outside of extreme pixel-peeping, such differences would be apparent.

Can I suggest the following test. Michael should make a 24"x36" print from the D800E shot, according to his satisfaction, then ask Jeff Schewe to make another print from the D800 RAW image of the same scene, using the same paper, ink, printer and profile etc, with the request that Jeff try to make the D800 print look as close as possible in quality, sharpness, color and contrast etc to the D800E print which Michael has previously produced.

Both prints should then be circulated to experienced photographers in a double-blind test to see if they can correctly identify which is which.

If most of the viewers are able to see the differences when holding the prints in their hands and viewing them from the close distance one might read a book, the prints should then be placed on a wall, side by side, and viewed from a more sensible distance equal to the diagonal of the print. If the differences can still be correctly identified in that situation, then I think there's no doubt that the D800E is a worthwhile improvement.

However, I'm still uncertain about the noise implications of sharpening under certain circumstances. Is it likely that deep shadows in a D800E shot will be noticeably cleaner as a result of the lower sharpening required?

When the images are shot at a high ISO where noise may be almost unacceptable, will the differences between the two cameras then be more noticeable, the D800E shot being either noticeably sharper or noticeably less noisy?
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BartvanderWolf
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« Reply #51 on: April 21, 2012, 07:58:51 PM »
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Having examined Michael's second, updated comparison of shots of a $20 bill after both have been sharpened, I'm beginning to think the resolution differences between the D800 and the D800E really are too small to be worth bothering about.

The differences in the unsharpened images are sufficiently great to become a concern, but appropriate sharpening seems to have narrowed the differences to a point where one really wonders under what circumstances, outside of extreme pixel-peeping, such differences would be apparent.

Hi Ray,

Consider this. In digital imaging, broadly (lens specifics aside) speaking, resolution is defined by two things:
  • Sampling density (assuming quality optics and good enough technique, i.e. proper use of a tripod, and perfect focus). Sampling the projected image with a finer discrete sampling grid will allow to reconstruct the original analog image more accurately. Since both the D800 and the D800E have an identical sampling density, there is no reason to expect any difference caused by this discriminator.
  • Amplitude of the Signal to Noise (S/N) ratio at the limiting resolution. The sole purpose of an Anti-Aliasing or Optical Low-Pass Filter (OLPF) is to reduce the amplitude of the signal at (and thus beyond) the Nyquist frequency. High signal levels above Nyquist will 'fold back' to coarser features with spatial frequencies below Nyquist. Due to the different sampling densities of Green versus Red/Blue, the 'strength' of the OLPF is usually under-designed, i.e. it's too weak to avoid all aliasing, and as a consequence leaves enough S/N to restore, in the focus plane.

That means that at the absolute Nyquist frequency limit (set 'in concrete' by the sampling density), there is usually enough signal left in the focus plane (despite the OLPF) to allow restoration to higher relative levels with clever sharpening. That restoration will not only boost the amplitude of the signal at the Nyquist frequency, but also in lower spatial frequencies, which enhances the so-called 3D look of images (which also explains why it also has an effect in smaller sized prints), because the overall MTF is boosted (also for lower spatial frequencies, coarser detail gains acutance). The lack of an OLPF boosts amplitude of the below-Nyquist spatial frequencies (which is welcome), in addition to the aliasing artifacts (with a high enough amplitude to cause occasional trouble, which is a nuisance).

Therefore it's not a real surprise that proper sharpening pretty well levels the playing field between both versions (with a slight advantage to to 'E' version IF aliasing doesn't spoil the party, which it will when you can least use it, AKA Murphy's law).

Cheers,
Bart
« Last Edit: April 21, 2012, 08:10:17 PM by BartvanderWolf » Logged
Ray
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« Reply #52 on: April 21, 2012, 09:19:11 PM »
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    • Amplitude of the Signal to Noise (S/N) ratio at the limiting resolution. The sole purpose of an Anti-Aliasing or Optical Low-Pass Filter (OLPF) is to reduce the amplitude of the signal at (and thus beyond) the Nyquist frequency. High signal levels above Nyquist will 'fold back' to coarser features with spatial frequencies below Nyquist. Due to the different sampling densities of Green versus Red/Blue, the 'strength' of the OLPF is usually under-designed, i.e. it's too weak to avoid all aliasing, and as a consequence leaves enough S/N to restore, in the focus plane.

    That means that at the absolute Nyquist frequency limit (set 'in concrete' by the sampling density), there is usually enough signal left in the focus plane (despite the OLPF) to allow restoration to higher relative levels with clever sharpening. That restoration will not only boost the amplitude of the signal at the Nyquist frequency, but also in lower spatial frequencies, which enhances the so-called 3D look of images (which also explains why it also has an effect in smaller sized prints), because the overall MTF is boosted (also for lower spatial frequencies, coarser detail gains acutance). The lack of an OLPF boosts amplitude of the below-Nyquist spatial frequencies (which is welcome), in addition to the aliasing artifacts (with a high enough amplitude to cause occasional trouble, which is a nuisance).

    Therefore it's not a real surprise that proper sharpening pretty well levels the playing field between both versions (with a slight advantage to to 'E' version IF aliasing doesn't spoil the party, which it will when you can least use it, AKA Murphy's law).

    Cheers,
    Bart


    Hi Bart,
    I understand the broad concept here, but there's also another truism; if the detail doesn't exist in the first instance, in the captured data, then no amount of sharpening can create it.

    If the fine detail which is close in resolution to the sensor's Nyquist limit, is of high contrast, has a reasonably high MTF, then I can understand that the detail may still be captured despite the OLPF, but with a very faint or reduced contrast. Clever sharpening may well restore such faint detail to the same contrast level as in the D800E capture.

    But supposing the contrast of that fine detail in the real scene being photographed, does not have good contrast. It may then be the case that the camera with the OLPF does not capture such detail at all, but the D800E does succeed in capturing the detail, albeit faintly.

    Clever sharpening might then restore such faint detail in the D800E image to something which is noticeable in a print.

    Cheer!  Ray
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    Hans Kruse
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    « Reply #53 on: April 22, 2012, 01:51:00 AM »
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    Having examined Michael's second, updated comparison of shots of a $20 bill after both have been sharpened, I'm beginning to think the resolution differences between the D800 and the D800E really are too small to be worth bothering about.

    The differences in the unsharpened images are sufficiently great to become a concern, but appropriate sharpening seems to have narrowed the differences to a point where one really wonders under what circumstances, outside of extreme pixel-peeping, such differences would be apparent.

    Can I suggest the following test. Michael should make a 24"x36" print from the D800E shot, according to his satisfaction, then ask Jeff Schewe to make another print from the D800 RAW image of the same scene, using the same paper, ink, printer and profile etc, with the request that Jeff try to make the D800 print look as close as possible in quality, sharpness, color and contrast etc to the D800E print which Michael has previously produced.

    Both prints should then be circulated to experienced photographers in a double-blind test to see if they can correctly identify which is which.

    If most of the viewers are able to see the differences when holding the prints in their hands and viewing them from the close distance one might read a book, the prints should then be placed on a wall, side by side, and viewed from a more sensible distance equal to the diagonal of the print. If the differences can still be correctly identified in that situation, then I think there's no doubt that the D800E is a worthwhile improvement.

    However, I'm still uncertain about the noise implications of sharpening under certain circumstances. Is it likely that deep shadows in a D800E shot will be noticeably cleaner as a result of the lower sharpening required?

    When the images are shot at a high ISO where noise may be almost unacceptable, will the differences between the two cameras then be more noticeable, the D800E shot being either noticeably sharper or noticeably less noisy?

    Thanks Ray for suggesting this test. I was about to suggest the same. Unless you provide such a double blind test no human being can escape from the confirmation bias we all suffer from Wink
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    aragdog
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    « Reply #54 on: April 22, 2012, 10:24:40 AM »
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    I am in line for an 800E.  I used to be a big photography fan..  In fact my Son worked for a great photographer Herman Leonard for some years.  But with the loss of all equipment in Katrina that ferver vanished.  But just lately have some Nikon Lens around and decided to pre order an 800E so will be very excited to receive it.  Appreciate the thoughts posted.   Now if I can just understand much of the digital workflow, this old man can get back to taking some photos.
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    Morris Taub
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    « Reply #55 on: April 22, 2012, 11:04:21 AM »
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    I am in line for an 800E.  I used to be a big photography fan..  In fact my Son worked for a great photographer Herman Leonard for some years.  But with the loss of all equipment in Katrina that ferver vanished.  But just lately have some Nikon Lens around and decided to pre order an 800E so will be very excited to receive it.  Appreciate the thoughts posted.   Now if I can just understand much of the digital workflow, this old man can get back to taking some photos.

    loved Herman Leonard's music photos...and saw a documentary with him going back home, to his studio, after that disaster...really sad stuff...

    give yourself some time to get a handle on digital workflow...read a lot about what others do or suggest, then adopt the 'methods' for processing and archiving that make the most sense 'to you' and for your needs...

    i've been using a D700 the last three years and it's great...will wait a bit to see more on the D800/e...then maybe upgrade, maybe wait...before I buy I'm hoping to play with one in a store, listen to it...the clack of the shutter/mirror slap on my D700 is very loud...hoping the d800 is much more quiet...one of the few criticisms i have of this lovely nikon body...
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    Slobodan Blagojevic
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    « Reply #56 on: April 22, 2012, 11:31:47 AM »
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    I am puzzled by what appears to be a rationalization that "a proper sharpening would negate the advantage the 800e has". I am not a scientist, but what I've learned so far about the subject matter is that in post processing you can improve/sharpen lens acutance (i.e., edge contrast) but you can not (much) improve lens resolution (i.e., fine detail). If so, no amount of sharpening would improve (much) the lack of fine detail in 800 (relative to 800e). No?

    Unless what you squints are saying is that, given the same lens, the amount of fine detail is the same in both cases, just blurred by AA more in 800 than in 800e, and that, with a proper reverse engineering of that blurring, one can come to the same starting point, i.e., the same amount of detail the lens is otherwise capable of. Is that it?
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    Slobodan

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    BartvanderWolf
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    « Reply #57 on: April 22, 2012, 12:41:25 PM »
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    I am puzzled by what appears to be a rationalization that "a proper sharpening would negate the advantage the 800e has". I am not a scientist, but what I've learned so far about the subject matter is that in post processing you can improve/sharpen lens acutance (i.e., edge contrast) but you can not (much) improve lens resolution (i.e., fine detail). If so, no amount of sharpening would improve (much) the lack of fine detail in 800 (relative to 800e). No?

    Hi Slobodan,

    No, proper sharpening is not the same as enhancing acutance by boosting edge contrast. Proper (deconvolution) sharpening actually restores the resolution of the original signal to what it was before the blur got added. You can see an example of it in this thread.

    So it's more than edge contrast, it's actual resolution that can be restored to a very large extend, only it's minus the aliasing artifacts because those spatial frequencies were attenuated before they were captured by a discrete sampling grid.
    If it were only edge contrast, then I'd be as puzzled as you are/were.

    Quote
    Unless what you squints are saying is that, given the same lens, the amount of fine detail is the same in both cases, just blurred by AA more in 800 than in 800e, and that, with a proper reverse engineering of that blurring, one can come to the same starting point, i.e., the same amount of detail the lens is otherwise capable of. Is that it?

    You've got it, that's it. Actual restoration instead of simulation.

    Cheers,
    Bart
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    « Reply #58 on: April 22, 2012, 06:29:26 PM »
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    The simple way to demonstrate if there is any real resolution benefit, is to do an objective comparison of a star target like the free one I proposed. In its center it will demonstrate if the limiting resolution differs or (probably) not by the diameter of the center blur, and how the sensitivity for aliasing differs at various angles by diverging patterns (in color if the demosaicing fails), all in a single shot. That single shot can be an in-camera JPEG and a Raw file if you want to simultaneously verify the quality of the in-camera JPEGs.

    Objectivity will help the readers, more than subjectivity/opinions (which will always be contested, this is the internet...) does.

    Cheers,
    Bart

    Bart,

    Agreed. Your sine-radial modified Siemens star chart provides an excellent means of quickly and objectively comparing and evaluating a wide range of sensor/lens characteristics. However, I would also very much like to see the full suite of SFR/MTF test results from Imatest---run by someone who is thoroughly familiar with the proper Imatest methodology to make valid comparisons between the D800 and the D800E. This should include using a lens that substantially out-resolves the 36MP sensor (one of the better Zeiss offerings that performs well at f/4 to f/5.6 should work well here, at least in the center of field). A plain vanilla raw converter like Dave Coffin's DCRaw would provide a pure linear conversion and eliminate possible bias in the raw converter.

    Further, the tests could be performed with a combination of no sharpening, optimized ACR/Lightroom sharpening and, as suggested, with a top Deconvolution sharpening algorithm (preferably optimized based on a careful evaluation of the PSF of each lens/sensor system). The charts could be either a well made sine pattern or slant-edge patterns with low to high contrast elements. If the same lens is used on both cameras and since these are essentially identical sensors at heart (except for the AA filters), the results should be quite relevant in isolating the effect of the AA filter difference.

    I think seeing the entire SFR/MTF plots for each of these cases, especially the response for both sensors at spatial frequencies near Nyquist (and at medium frequencies where the apparent "3D" effect is seen), would make clear any advantages the D800E might have over the D800. Specifically, if optimized sharpening performed on the image from D800 sensor is able to boost the response curve at and below the Nyquist cutoff enough to substantially match the response curve from the (optimally sharpened) D800E image, then the D800 may be the better choice. It would also be interesting to see the response curve above Nyquist on both sensors to show the likelihood of aliasing, although the radial pattern of your star chart might better illustrate this if the resolution of the test lens is not symmetrical.

    I'm sure one of the commercial sites will eventually perform MTF/SFR testing with Imatest or DxO software---but the near total lack of published testing methodology on these sites (raw conversion?, chart contrast?, sharpening?, focus distance?, etc.) has rendered me highly skeptical of their results. Undecided

    EDIT: The robust Imatest noise module might also objectively answer the difficult question of how much the relative noise levels suffer on the D800, due to more aggressive required sharpening, compared to the D800E.

    Kind regards,
    Bob
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    ErikKaffehr
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    « Reply #59 on: April 22, 2012, 11:19:14 PM »
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    Hi Bart,

    Restoring an image using deconvolution needs a decent PSF (Point Spread Function), and I'm not sure we have it. The article you refer to was about restoring an image with diffraction, and it seems that using a gaussian (bell curve) as PSF yields decent results, but I don't know what happens with an image formed by an AA-filter.

    Diglloyd compared the Leica S2 with a Nikon D800. The Leica had moiré "all over the place" while the Nikon had very little. My guess is that Lloyd Chambers ("Diglloyd") will reshoot the same image with the D800E. Moiré is an interaction between sensel pitch and structure pitch in the subject, so Moiré may or many not arise. Occurrence of moiré pretty much indicates that the imaging system aliases but the absence of moiré doesn't tell anything.

    Best regards
    Erik

    Hi Slobodan,

    No, proper sharpening is not the same as enhancing acutance by boosting edge contrast. Proper (deconvolution) sharpening actually restores the resolution of the original signal to what it was before the blur got added. You can see an example of it in this thread.

    So it's more than edge contrast, it's actual resolution that can be restored to a very large extend, only it's minus the aliasing artifacts because those spatial frequencies were attenuated before they were captured by a discrete sampling grid.
    If it were only edge contrast, then I'd be as puzzled as you are/were.

    You've got it, that's it. Actual restoration instead of simulation.

    Cheers,
    Bart
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