Hello Paul, I was under the impression that noise reduction had to do with hot pixels. At slow shutter speeds some pixels may get hot and cease to function properly. The noise reduction finds them and masks them out for that shot. I don't think it has any bearing on ISO speed. I also thought it only functioned once the shutter speed was down around 1/2 sec or so. See my PUG entry this month. Taken at ISO 200 with noise reduction on. The blacks are black and there are no hot pixels.
Noise/grain reduction is a whole different ballgame. My understanding is that you leave it on all the time and it only kicks in on the slow shots. Why turn it off? Because at slow speeds it must actually take two shots - one a black shot to find the hot pixels. So if you want to mask them out yourself later, you can shoot much faster with it off. I leave it on all the time. -- Best regards, Bruce Sunday, February 8, 2004, 10:11:28 AM, you wrote: PS> What's the consensus opinion on noise reduction? It would seem to be PS> desirable at ISO 1600 or 800, but will it result in a loss of detail at PS> slower speeds? PS> Paul
