The Naked Sensor - Sean Reid on LL

[groovyone]

The Naked Sensor

Sean covers the advantages of cameras without AA filters.

Originally Posted by Reid

Their sensors are far from naked. But by stripping away the AA filter (or, in Nikon's case, using a system that is supposed to do the equivalent) they're getting closer to being able to render a lens' drawing without degrading it.

[tc95]

Sean...has always been a supporter of Sigma...I love his write-ups...!!!

[groovyone]

It is a good read. I may have to subscribe to his site for his D800E and X Pro-1 reviews.

[jeffkohn]

Sean covers the advantages of cameras without AA filters.

He also glosses over the disadvantages, and IMHO comes across pretty ignorant of sampling theory and how OLPF's work. Total puff-piece, but then again these kinds of articles from people who don't know the tech stuff nearly as well as they think they do are getting all too common on LuLa.

[groovyone]

So, outside the moire, what are the disadvantages?

[jeffkohn]

Originally Posted by groovyone

So, outside the moire, what are the disadvantages?

Moire is the most obvious problem - when it shows up - but edge aliasing and color aliasing occur far more often. It's the color aliasing, aka false color or color sparklies, that I particularly don't like; to me it makes images look digital and less film like, with that crunchy look similar to over-sharpened digital images. For some this is a welcome trade-off for out-of-camera sharpness, and they actually like the crunchy look (probably a lot of the same folks who like overdone HDR ).

BTW Reid's assertion that only Bayer-filtered sensors have use for AA filtering is not correct. RGB sensors such as Sigma's won't get color aliasing/moire, but they can still have edge aliasing or monochromatic moire.

To me the advantage of no OLPF is overstated by comparing out-of-camera images. Once you use deconvolution-based capture sharpening on the AA-filtered image, the difference in sharpness and detail is greatly reduced. In fact I believe it was Sean Reid who in one of his comparison articles showed that a D3x image with deconvolution sharpening not only had fewer artifacts compared to a Leica M9 image, but also slightly greater detail. Granted the D3x has a slightly higher MP count; but if the advantage of an OLPF-free design were as great as some would have you believe, the D3x wouldn't come out on top in that comparison.

I'm not completely dismissing the D800E; it may be that 36mp full-frame is enough resolution to minimize artifacts to acceptable levels for me (I know from looking at M9 samples that 18mp isn't enough). One thing that will be interesting is that between the D800 and D800E we'll have the ability to examine the pros/cons of AA filtering in otherwise-identical cameras. I'll be interested to see how D800 images with deconvolution sharpening compare to D800E images.

[groovyone]

Interesting points. I learned some new stuff.

That is interesting about the D3x since it has the same 24MP sensor as the A900, and the 18MP M9 compared very well in resolution to the 24MP A900, but I never did see any artifact comparisons.

The D800E also still claims to use some sort of optical filter, just no AA, so I wonder if that will aid in the reduction of any artifacts.

Thanks, Jeff!