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Author Topic: D800E Moire question  (Read 6774 times)
GeraldB
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« on: February 09, 2012, 10:59:26 AM »
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I'm contemplating upgrading from my D300 to a D800E. I've not used a camera before that does not sport an AA filter. So my question to those who have used one say a MFB or Leica how easy is it remove moire in post, how likely is one to see moire in architectural/city shots like this: http://www.geraldbloch.com/paris/h2e0bd686#h2e0bd686

My understanding is that it is most likely to be seen on fabrics and something like a fly screen on a window. Presumably one cannot see moire through the viewfinder, what about on live view? If its visible while shooting can you remove it by small change in viewpoint?

thanks
Gerald
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BJL
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« Reply #1 on: February 09, 2012, 01:08:06 PM »
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Presumably one cannot see moire through the viewfinder, what about on live view? If its visible while shooting can you remove it by small change in viewpoint?
I would think that if you zoom in live view to "100% pixels", you might see the same moiré as in the final output, but I am not sure.
On the other hand, the normal unmagnified view is of no help: if anything, if LV just subsamples the sensor signal (reading just as many photosites ad needed), you could get moiré in LV that is not present in the image recorded.
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Dustbak
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« Reply #2 on: February 09, 2012, 01:13:56 PM »
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Not sure if you can see moire via live view my MF equipment only has a rudimentary form of live view meant to be used solely for focussing purposes.

There are a number of ways you can fight moire. Changing viewpoint can help, stopping down further causing some diffraction will help too. When you do encounter moire it can be dealt with via software too (either built-in moire reduction in the raw converter) or via PS. Problem is when you need to do this on 100's of files! Dealing with the occassional moire on some files I consider to be a total non-event.

In your example I doubt it will be an issue. B&W shot, at night and stopped down pretty far.

I have had lots of moire with 11MP, 22MP and less with 39MP. Now with 60MP most of it is gone. This Nikon has an equivalent of around 70MP when compared to MFDB I reckon. I don't expect moire to be a huge issue.

I have ordered a D800e (as a convenient backup for my H4D or another companion for my D700).
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GeraldB
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« Reply #3 on: February 09, 2012, 01:47:41 PM »
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Stopping down or changing viewpoint are only effective tactics if one knows that moire is occurring. If you cannot see it in LV or viewfinder makes it kinda difficult. So it depends on how likely moire is in non nature photos, nature being irregular mostly. Seems like one can only wait and see what the results are when they become available. Thanks for your replies.
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Slobodan Blagojevic
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« Reply #4 on: February 09, 2012, 01:51:07 PM »
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Just a quick note: moire is possible even with cameras with AA filters. I started a thread some time ago about my experience with Canon 40D, and you might find some replies there helpful:

http://www.luminous-landscape.com/forum/index.php?topic=42751.msg360464#msg360464
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JeffKohn
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« Reply #5 on: February 09, 2012, 02:42:19 PM »
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Moire is not the only problem you have to worry about in Bayer-sensor camera with no AA filter.
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GeraldB
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« Reply #6 on: February 09, 2012, 05:04:02 PM »
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Thanks Slobodan, helpful ideas on how to deal with it. I believe LR4 has a moire brush, so perhaps I'm worrying about nothing.

Jeff, whats the other thing?
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Anders_HK
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« Reply #7 on: February 09, 2012, 05:58:52 PM »
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FWIW when I stepped from 20MP ZD to 28MP Aptus 65 the worry of moire disappeared quick, and more so now with 80MP. With more pixels moire is less of a problem due to the finer resolution used to capture the fine patterns that may otherwise cause moire. It may well be that with D800E you would experience very rare moire problems or basically none at all depending on your subjects.

Best regards,
Anders

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jonathanlung
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« Reply #8 on: February 09, 2012, 07:57:56 PM »
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I have had lots of moire with 11MP, 22MP and less with 39MP. Now with 60MP most of it is gone. This Nikon has an equivalent of around 70MP when compared to MFDB I reckon. I don't expect moire to be a huge issue.

I thought moiré was a function of resolution, independent of format (ceteris paribus). Someone please correct me if I'm mistaken.
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ErikKaffehr
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« Reply #9 on: February 09, 2012, 08:49:33 PM »
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Hi,

It's a function of lens MTF and pixel pitch. I have a Sony A55 SLT which has the same pixel pitch as the D800. The A55 seems to have a weak AA filter, as I see a lot of Moiré and aliasing in test shots. Real life may be another thing.

Stopping down to f/11 or something should cure Moiré effectively but would loose some sharpness. It seems that even the Sony NEX7 has issues with Moiré, if the lens is good enough, although having very small pixels.

Best regards
Erik


I thought moiré was a function of resolution, independent of format (ceteris paribus). Someone please correct me if I'm mistaken.
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Mike Guilbault
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« Reply #10 on: February 09, 2012, 09:45:27 PM »
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My main concern for moiré with 800E was shooting interiors with lots of fabric, shear curtains and such.  But most of this is shot at f11 or smaller apertures, usually f/16.  I've seen moiré with my D300 and even with my D700, but not so much at these smaller apertures.  So I'm really hoping the D800E will be the same.  I'll be waiting for some sample RAW files to make my final decision whether to "E" or not. 
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LKaven
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« Reply #11 on: February 09, 2012, 09:50:37 PM »
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Moire is not the only problem you have to worry about in Bayer-sensor camera with no AA filter.

The D800E has a filter stack, but the effects of the OLPF are nullified.
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Schewe
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« Reply #12 on: February 09, 2012, 10:38:33 PM »
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Thanks Slobodan, helpful ideas on how to deal with it. I believe LR4 has a moire brush, so perhaps I'm worrying about nothing.

The LR4 moiré adjustment brush works very, very well for color moiré and a decent job on luminosity moiré. We'll have to see some raw samples from the D800 to see how well the LR4 moiré brush works...so we'll see. I think it will be less of an issue. The Leica M9 also has not AA filter and was the source of a lot of test files for developing the moiré brush for LR4.
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John Camp
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« Reply #13 on: February 09, 2012, 11:20:32 PM »
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I'd point out at the possible expense of being obvious that if you shoot test shots for moire, you'll eventually get some, because you'll be shooting the kinds of patterns that provoke it. My feeling is the resolution on the plain-vanilla D800 will be so good that if you shoot a lot of fabrics (which I would think is where you'll see most moire, because of the fine and repetitive spacing of the elements) then maybe you should just go with the 800. The Nikon comparison shots of the kimono with the plain D800 you can clearly see individual threads and stitches in the fabric, and I don't know that anyone who shoots a lot of fabrics would need any more resolution than that. I mean, what would it be for? Moire could pop up in other places (shots of TV screens, possibly in small tile patterns shot at a distance so the patterns replicate the tiny tight patterns of fabric) but I think those situations would be rare indeed.

Then, there's the working process to be considered. I suspect people who shoot a lot of fabrics could be the kind of person who might make a hundred shots in a day, and plan to use all of them -- sample shots, for example. And it would be a pain in the ass to remove the moire from a hundred shots on a daily basis. For landscapers, however, don't usually use all 100 shots in a day, and moire-producing patterns are much rarer. A landscaper may shoot a hundred shots, but may choose only one or two (or maybe none that day) to actually print. So, he's dealing with a much smaller project in removing moire -- he finds it less commonly, and processes fewer pictures.

I used an M8 for several years, with very good glass, with all kinds of general subjects, and occasionally saw moire...but really, not all that often, not so much that it bothered me. But really, with resolution as good at the D800, I see really little purpose for a general shooter like myself to go with the 800e.   
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ErikKaffehr
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« Reply #14 on: February 09, 2012, 11:21:34 PM »
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Hi,

If you are shooting at f/11 or f/16 the diffraction will reduce sharpness anyway, so I guess that you would see little difference in sharpness AA-filter or not.

Best regards
Erik


My main concern for moiré with 800E was shooting interiors with lots of fabric, shear curtains and such.  But most of this is shot at f11 or smaller apertures, usually f/16.  I've seen moiré with my D300 and even with my D700, but not so much at these smaller apertures.  So I'm really hoping the D800E will be the same.  I'll be waiting for some sample RAW files to make my final decision whether to "E" or not. 
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jeremyrh
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« Reply #15 on: February 10, 2012, 04:25:57 AM »
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Can someone say what is the relationship between the AA filter characteristics and the pixel size? Is it usually a strict function of the Nyquist frequency?

I am wondering if, at such small pixel sizes, the AA filter does anything more than most reasonable lenses are already doing? Anyone done the research, and care to share the answers?
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BartvanderWolf
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« Reply #16 on: February 10, 2012, 05:15:45 AM »
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Can someone say what is the relationship between the AA filter characteristics and the pixel size? Is it usually a strict function of the Nyquist frequency?

Sort of, kind of. The AA-filters (one horizontal, one vertical), each with different thickness tuned to the distance to the sensels, is designed to reduce the modulation of the highest spatial frequency detail as it approaches the Nyquist frequency, by spreading the signal for a single sensel over roughly 4 sensels.

One of the design trade-offs is that the Green and the Red/Blue filtered sensels have a different Nyquist frequency for the chroma part of their information. The Luminance information has a uniform Nyquist frequency because all sensels contribute some luminance information. It's the difference between luminance and (Green vs Red/Blue) chroma aliasing that can cause false color artifacts. AA-filters reduce that risk. They also reduce stairstepping (AKA jaggies) on high contrast edges and lines. It is not only repetitive structures near the limiting resolution that cause aliasing artifacts, but they stand out more because they disrupt a predictable pattern, something human vision is sensitive to.  

Quote
I am wondering if, at such small pixel sizes, the AA filter does anything more than most reasonable lenses are already doing? Anyone done the research, and care to share the answers?

While a poor lens design, or diffraction, or defocus, all help to reduce the amplitude of the higher spatial frequencies, they are much less efficient than an AA-filter. An AA-filtered image can be largely restored to the original detail level by deconvolution sharpening, but without many of the artifacts. An image taken without an AA-filter will only suffer more from sharpening.

A direct comparison with MF sensors without AA-filter is not straight forward, because of their larger sensels, usually no microlenses, and larger subject magnification factor (the same FOV is spread over a larger area, so detail is larger per pixel). MF cameras also use smaller aperture numbers to achieve a certain DOF, or have less DOF and thus more defocused areas.

We'll have to wait and see what the specific design of the D800 E's small sensels and their microlenses brings. The effects will vary by lens and diffraction/defocus amount, and subject matter.

Cheers,
Bart
« Last Edit: February 10, 2012, 05:18:46 AM by BartvanderWolf » Logged
NigelC
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« Reply #17 on: February 10, 2012, 06:11:12 AM »
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An AA-filtered image can be largely restored to the original detail level by deconvolution sharpening, but without many of the artifacts. Cheers,
Bart

deconvolution sharpening - does capture sharpening in ACR/Lightroom and/or smart sharpen in photoshop fall within this category?
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Walter_temp
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« Reply #18 on: February 10, 2012, 06:31:19 AM »
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deconvolution sharpening - does capture sharpening in ACR/Lightroom and/or smart sharpen in photoshop fall within this category?

Yes and no! http://www.luminous-landscape.com/forum/index.php?topic=45038.msg378027#msg378027

Ciao, Walter
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Dustbak
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« Reply #19 on: February 10, 2012, 10:04:22 AM »
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I thought moiré was a function of resolution, independent of format (ceteris paribus). Someone please correct me if I'm mistaken.

Not sure what you are getting at here, unless you are nitpicking on terms. The resolution numbers mentioned here are from the MF backs I owned. The pixel pitch is getting smaller every time the resolution went up (11/22, 39, 60) since the sensor remained more or less the same size. Moire got lesser and lesser. No theory here, just my experience and over 50K of fabric shots per year.

Actually I used to focus on my 39MP back for the moire. As soon as I had moire I knew for sure that was the sharpest I could get it. I did do a multishot after that so moire would not be an issue. Moire is a great sign of max focus Smiley

The Nikon would be getting a pixel pitch around that of the 60/80MP backs....
« Last Edit: February 10, 2012, 10:10:30 AM by Dustbak » Logged
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