The following sites contain some useful information regarding the physical sizes of certain digital camera CCDs, pixel sizes in microns, and noise characteristics and gains at different ISO levels.Roger Clark's compilation of gain, readout noise, detector and pixel sizes for a variety of digital cameras.Gain, readout noise in ADU and electrons, pixel sizes etc for EOS 10D and EOS 20D. Includes a nice set of examples astro-photography images and dark frames.Why is this important? Its related to a project I'm working on at the moment. This kind of information is very difficult to find on manufacturer's sites, as they're catering to an audience who has been make to think that number of megapixels is the only metric of value.Other useful links:dcraw: Read and convert RAW files (of all the various types).rawtran: A wrapper around dcraw to support better conversion of RAw to FITS than the cruder method suggested by dcraw. This is related to the munipack software package.