Add to the list: color compensation filters. When you adjust channel gains to make a daylight balanced sensor work in tungsten light (or visa versa) you increase noise in the channel you've boosted. So, as Julia mentioned in this post, and I have mentioned countless times over the years, an 80A or 80B filter is very useful on a daylight balanced DSLR like a Nikon.

Here's a nice post with test pictures.

http://forums.dpreview.com/forums/read.asp?forum=1021&message=21649498

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Ciao! Joe

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