[QUOTE="Andrew Reilly"]\nJPEG is 8 bits per colour, but that is *after* gamma correction, which is\nsomething of the same sort of logarithmic encoding as u-law or A-law in\ntelephone systems. So JPEG's 8 bits (can) represent about 12 bits of\nlinear dynamic range (RAW). Modern digital cameras often have some pre-\njpeg processing that can boost shadows a bit, so the recorded dynamic\nrange can be a good bit higher.[/QUOTE]\n\nThat is basically correct, and a very good comparison.\nHowever, the particular gamma correction with JPEG gets\na bit over 9 stops of dynamic range.\n\nThat compares with u-Law encoding of telecommuncations\nvoice frequency circuits, where the SNR of a voice\nchannel cannot be greater than 37 dB. Which says that\nif, for example, u-Law were used for the gamma\ncorrection in JPEG it would result in only about 6 stops\nof dynamic range.