I've noticed our 40D's are good to iso 400, and they get a tad noisy at 800. I don't know if you have found the same. That being said, iso 800 noise is much better than film of iso 400 so we are ahead of the curve. I have heard good things about a photoshop plugin called, "noise ninja" and plan on trying it out soon. I'll let you know how it works out because I'm shooting quite often at 800 or higher...