Price-Whelan made a remarkable discovery today—which may be false or an error of some kind, so don't quote me—that commercial digital cameras do not always subtract the dark frame, and the dark currents of the pixels are significant and vary from pixel to pixel. If this is right, we are going to be able to vastly improve the sensitivity of the cameras we have. Time to start writing the paper!
Do you mean that the camera takes a dark frame, and then doesn't bother to subtract it? That would certainly be surprising. Or do you mean that some cameras just don't take a dark frame at all?
ReplyDeleteOn my Pentax K10D, there's a setting (called "Noise Reduction") to control whether a dark frame is taken after the exposure. Regardless of the setting, I don't think it ever takes a dark frame if the exposure is sufficiently short.