If you haven't already read them I suggest that you look at the "Aliasing" entry in the glossary on this site:http://www.dpreview.com/.../learn/?/Glossary/Digital_Imaging/Aliasing_01.htm.

And Wikipedia:http://en.wikipedia.org/wiki/Anti-aliasing.

AFAIK the main reason for anti-aliasing is to smooth "jaggies"..

I think that there are very few cameras without anti-aliasing filters. The Leica M8 is the only one that I know of and you might want to read the review on this site.Chris R..

You can have the AA filter removed if you want to go to third party. You can pick up amazing levels of detail with it removed..

Http://maxmax.com/nikon_d200hr.htm.

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BA baracus wrote:.

You can have the AA filter removed if you want to go to third party.You can pick up amazing levels of detail with it removed..

But what about unwanted side effects?..

Pronounced Moire effects for one thing..

Linslus wrote:.

BA baracus wrote:.

You can have the AA filter removed if you want to go to third party.You can pick up amazing levels of detail with it removed..

But what about unwanted side effects?..

Linslus wrote:.

BA baracus wrote:.

You can have the AA filter removed if you want to go to third party.You can pick up amazing levels of detail with it removed..

But what about unwanted side effects?.

Moire and jaggies in some situations. The link I provided previously has sample images. If you dig around on that site there are many examples..

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Linslus wrote:.

Does the AA-filter do anything else than preventing moir patterns?.

That's it's basic purpose: eliminating false color due to color moir. Of course, it has side effects like reducing sharpness. On some recent Canon DSLR models, the front anti-aliasing filter is also used as a dust-shaker plate and to carry the dichroic IR reflective coating (those are simply mechanical issues, unrelated to the actual functioning of the anti-aliasing filter)..

How is this handled on cameras that doesn't have this filter?.

Digicams don't need anti-aliasing filters, because the lens is pretty much incapable of projecting an image with details above the Nyquist limit with any remaining contrast at all..

Cameras with Foveon sensors don't need anti-aliasing filters because they aren't subject to color moir. They do get ordinary moir, but that's typically not something that people are concerned about. They'd rather have the sharpness..

Occasionally a camera maker would rather have the sharpness and put up with the possibility of color moir. In that case they'll either install weak anti-aliasing filters or omit them entirely..

For the same reason, a few people choose to have their filters removed. This site shows some sample results:http://www.maxmax.com/hot_rod_visible.htm.

In a few cases such as the Leica M8, there may be optical challenges that lead the manufacturer to omit anti-aliasing filters. (I'm speculating that's the situation with the M8, I don't know that as a fact.)..