long exposure noise reduction

[TeddyLovessss]

Canon 20D's C. Fn-02 is long exposure noise reduction (basically works with exposure of 1 second or longer). i believe this works for RAW images, but i'm just not sure. i mean, maybe it just works for JPG images? can somebody clarify this?

[lancea]

It applies to whatever format you choose to save as. In case you're interested - someone posted an explanation a month or so ago. The exposure takes twice as long because it takes the shot, then does another shot of the same duration but without opening the shutter. The noise from the second "shot" is "subtracted" from the first.

[TeddyLovessss]

thanks. i wish i could find that post :)