I just read an article that said the cleanest image you can get is by using a camera's "native ISO" rather than whatever zero's out your exposure meter. It said that Canon's native ISO is 80 and you should increase it in increments, from 80 to 160 to 320, etc. Whereas Nikon's "native ISO" is 120 and should be increased to 240, 480 etc, in other words doubling the ISO. Any other number just takes, for example, ISO 100 and digitally adds ISO to increase the brightness artificially. I haven't had a chance to shoot at 120 yet today and something tells me the difference in noise will probably be virtually undetectable. Just wondering if I dreamed this or what?