The low ISO performance on the D10 was very good. Noise was in short supply below ISO 200, and fine detail and sharpness were noticeably better than other cameras in its class. Subjects get visibly grainier between ISO 200 and 400, and at ISO 400 things start to look smeary. At ISO 800 it looks like something's smeared on the lens. You can pretty much write off using ISO 1600.