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Author Topic: D800E, moire, and diffraction  (Read 3886 times)

krex

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D800E, moire, and diffraction
« on: April 04, 2012, 11:37:36 pm »

I'm debating the relative merits of the D800 vs. the D800E for landscape photography and am looking for clarification on something that's puzzling me.  I've read more than a few places online that if you're going to shoot at smaller, diffraction-inducing apertures, you might as well get the D800 because you're negating the sharpness advantage of the D800E. It seems to my logic that the loss of sharpness from the OLPF in the D800 would compound with the loss of sharpness from diffraction such that, under identical levels of diffraction, the D800E would still produce a sharper image than the D800, all things being equal otherwise. If the main drawback of the D800E is the risk of aliasing/moire, and the smaller apertures common to landscape photography for maximizing DOF help to reduce or eliminate moire, wouldn't the D800E still have an advantage over the D800 for landscape photography by producing sharper images, even if they aren't optimally sharp due to diffraction? What am I missing?  I realize moire situations are relatively rare in landscape photography, but barn shingles and wave patterns in sand dunes are two examples that come quickly to mind.  Thanks in advance for any input. I've already pre-ordered the D800 but am wondering if the D800E wouldn't be the better choice for use almost exlcusively in landscape photography.
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Bart_van_der_Wolf

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Re: D800E, moire, and diffraction
« Reply #1 on: April 05, 2012, 03:19:48 am »

I'm debating the relative merits of the D800 vs. the D800E for landscape photography and am looking for clarification on something that's puzzling me.  I've read more than a few places online that if you're going to shoot at smaller, diffraction-inducing apertures, you might as well get the D800 because you're negating the sharpness advantage of the D800E. It seems to my logic that the loss of sharpness from the OLPF in the D800 would compound with the loss of sharpness from diffraction such that, under identical levels of diffraction, the D800E would still produce a sharper image than the D800, all things being equal otherwise.

Hi,

That is basically correct. The resulting image will have a mix of the OLPF and diffraction blur, where diffraction alone will produce a higher signal amplitude (higher MTF).

Quote
If the main drawback of the D800E is the risk of aliasing/moire, and the smaller apertures common to landscape photography for maximizing DOF help to reduce or eliminate moire, wouldn't the D800E still have an advantage over the D800 for landscape photography by producing sharper images, even if they aren't optimally sharp due to diffraction?

That's probably the case, but I do not really understand what it is that they did with the OLP filter. I understand what they are saying in their diagrams, but I don't see how that is optically possible. Therefore it's difficult to predict, especially in combination with different lenses, how much aliasing risk remains with the D800E.

Quote
What am I missing?  I realize moire situations are relatively rare in landscape photography, but barn shingles and wave patterns in sand dunes are two examples that come quickly to mind.  Thanks in advance for any input. I've already pre-ordered the D800 but am wondering if the D800E wouldn't be the better choice for use almost exlcusively in landscape photography.

Aliasing is not only an isue with small repetitive patterns, it will also manifest itself as jagged edges, and will create difficulties with sharpening (e.g. to restore from diffraction).

Cheers,
Bart

P.S. I don't think there is much resolution difference between a properly sharpened D800 image, and a D800E image, except for the aliasing risk. In the D800 examples I've seen sofar, sharpening in general was sub-par.
« Last Edit: April 05, 2012, 03:27:05 am by BartvanderWolf »
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== If you do what you did, you'll get what you got. ==

jaapb

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Re: D800E, moire, and diffraction
« Reply #2 on: April 05, 2012, 04:28:45 am »

In the D800 examples I've seen sofar, sharpening in general was sub-par.

I agree with Bart, also many of the comparisons deal with noise and some comparisons are more equal than others  :D
I too have a D800 on order because I believe that proper sharpening is easier accomplished than dealing with aliasing artifacts.
Now just waiting for this thing to arrive.

Jaap
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krex

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Re: D800E, moire, and diffraction
« Reply #3 on: April 06, 2012, 11:17:00 pm »

Thanks to both of you for the feedback.  I just couldn't understand why so many people were advising that if you were going to shoot at smaller apertures you might as well stick with the D800, as if the D800E wouldn't still be relatively sharper.  Still haven't made a decision yet, but I appreciate the input.
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ErikKaffehr

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Re: D800E, moire, and diffraction
« Reply #4 on: April 07, 2012, 01:40:10 am »

Hi,

I agree with Bart, mostly.

One point I feel is that either OLP filtering or diffraction would dominate, depending on stopping down. As I see it both OLP filtering and diffraction add a PSF (Point Spread Function). The OLP filter is essentially a beam splitter. So I guess the PSF is small and well defined but ugly. Diffraction  has a PSF which is more similar to a bell curve. Some of the contrast lost due to diffraction may be regained with proper sharpening.

Once the peak of bell curve is broader than the PSF from the OLP filter diffraction  will dominate over OLP filtering. So, OLP filter will dominate at large apertures and diffraction will dominate at small apertures in between the PSFs will be superimposed.

Another point I would make is that although I believe that much of the OLP-filtering can be compensated for in sharpening, the kind of sharpening needed will also enhance noise.

Best regards
Erik


Hi,

That is basically correct. The resulting image will have a mix of the OLPF and diffraction blur, where diffraction alone will produce a higher signal amplitude (higher MTF).

That's probably the case, but I do not really understand what it is that they did with the OLP filter. I understand what they are saying in their diagrams, but I don't see how that is optically possible. Therefore it's difficult to predict, especially in combination with different lenses, how much aliasing risk remains with the D800E.

Aliasing is not only an isue with small repetitive patterns, it will also manifest itself as jagged edges, and will create difficulties with sharpening (e.g. to restore from diffraction).

Cheers,
Bart

P.S. I don't think there is much resolution difference between a properly sharpened D800 image, and a D800E image, except for the aliasing risk. In the D800 examples I've seen sofar, sharpening in general was sub-par.
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Erik Kaffehr
 

Pingang

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Re: D800E, moire, and diffraction
« Reply #5 on: April 07, 2012, 04:04:58 am »

I have tried the D800, prefer it over my D3X, but I will wait for D800e for final purchase decision. I got my 5DIII as well, very nicely built and much improved AF.

Pingang
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Guldsmed

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Re: D800E, moire, and diffraction
« Reply #6 on: April 26, 2012, 11:12:53 am »

After reading the D800/D800E shoot out, where the problem of Moire was notably absent, I am wondering about moire in pics of natural features. I do know, that fabrics especially but also other regular man made objects are the most dangerous re the problem, and that natural landscapes, do not induce them. But what about the structure in bird feathers or the scaling on a butterfly wing, features that also have a great degree of regularity?

best wishes

Jan F. Rasmussen, Denmark who has a pre order for D800, but is attracted to D800E instead...
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telyt

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Re: D800E, moire, and diffraction
« Reply #7 on: April 26, 2012, 01:39:15 pm »

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Guldsmed

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Re: D800E, moire, and diffraction
« Reply #8 on: April 27, 2012, 01:20:36 am »

Thx Telyt!
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