D800E DX crop mode and AA filter

Started Nov 5, 2012 | Discussions thread
PK24X36NOW Senior Member • Posts: 1,877
Re: D800E DX crop mode and AA filter

Leo360 wrote:

Robin Casady wrote:

Leo360 wrote:

I am trying to understand whether canceled AA filter in D800E can cause more moire problems when shooting in DX cropped mode.

The "cancelled AA filter" does not ´╗┐cause´╗┐ moiré, it just fails to obscure it.

Moire artifacts are the manifestation of the above Nyquist frequency (fine details) aliasing. D800E in DX crop mode has the same sampling rate per angle of field of view as D7000 (1.5 times less than in full 36MP mode). Therefore, the moire will be effectively equivalent to the D7000 with AA filter removed. Did anyone notice increased moire when shooting D800E in DX crop mode? Would D800 be better choice for shooting in DX mode?

Cropping will not affect moiré generation. It has to do with the texture of the subject and the scale that texture is when it falls on the sensor. Changing the focal length of the lens and/or distance from camera to subject is what affects moiré.

If you put a camera on a tripod and shoot a subject that produces moiré in the center of the photo, then simply change the camera to DX mode (same lens and camera position) you will get the exact same moiré.

Robin, to compare apple to apples I keep the scene invariant and maintain the same angle of view. Therefore, entering DX crop mode is accompanied by 2/3 focal length reduction. This in turn leads to 1.5 times reduction in Nyquist frequency in angular sampling (only 16MP cover the same scene) and more aliasing from fine details present in the frame. And there is no low-pass-filter (AA) to cut off those out-of-band frequencies leading to more moire. I am still under impression that D800E in DX mode is a fancy version of D7000 minus AA-filter.

Yes, exactly. Assuming you're taking the same picture in DX mode that you would in FX mode (otherwise the comparison becomes pretty meaningless), the DX mode shot has less pixels, a lower Nyquist frequency and a higher likelihood of moire.

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