Do you really need an anti-aliasing filter? The answer is not easy - as we know a good filter can dramatically reduce digital artifacts (for example moire) while taking pictures or shooting movies, on the other hand there's a price - you lose a little bit of sharpness. Sean Reid wrote a great article on the matter called "The Naked Sensor" (you can find the full version here). What would be really cool is to have a camera which would allow to turn the AA filter on and off but right now let's focus on Sean's thoughts.
First of all he believes that pros prefer to remove the AA filter:
"At some point in the not too distant future we were going to be seeing more and more cameras with either very light AA filters or none at all. In my mind, then and now, the AA filter is one of the key elements that "throttles", so to speak, the potential of a digital camera. I noticed this, emphatically, when I was testing a set of Zeiss ZF SLR lenses on both the Nikon D700 and the Canon 1Ds Mk III (the latter via an adapter). Again and again I saw much higher resolution (from the exact same lens) when it was mounted on the 1Ds Mk III. Now, of course, the files from the Canon were dimensionally larger (given its 21 MP sensor as compared to the 12 MP sensor of the Nikon) but what I came to realize was that what I was really seeing were differences between a camera with a stronger AA filter (the Nikon) and one with a weaker AA filter (the Canon). Like many photographers, I’d long known about this difference but that experience sharpened my sense of how important this factor could be."
He also reminds that the higher end of digital photography has long done without AA filters.
"Kodak brought this approach to DSLRs and Leica brought it to their DMR back, their DRFs and their S2. But this strategy comes at a price, of course - the photographer sometimes has to deal with correcting color moire. I'm sure that many professional photographers like myself know the sinking feeling of being under deadline for a client or art director and having to spot-correct moire in dozens or more pictures from a shoot. I recall once having to do this for about fifty pictures made during a wedding shoot (done mostly with my trusty M8.2). The challenge of life without an AA filter is real and it can sometimes create a lot of post-processing work. I should note, however, that color moire certainly can be *spot* corrected. One doesn't need to, and I would say shouldn't, apply the corrections to the whole picture. Not all photographers will want to take on the correction of moire in exchange for a gain in resolution (a fact that Nikon has implicitly acknowledged in making two versions of the D800) but I'm glad to see more options appearing for those of us who are."
So next time you buy a camera, will you choose one without the AA filter?
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