On Wed, 2004-09-15 at 11:21, Gary Lawton wrote: > A JPG file is an 8bit compressed TIFF file. However, JPG compression is > "lossy" meaning that data is thrown away during the compression process. > > The conversion back to TIFF will not recover data that was lost during > the compression. Nor can it recover the 8bits of data that were > discarded from the 16bit sensor reading. > > It'll work, it just wont give you the best quality > Yes, I know all that in advance, but tell me also when a camera saves a picture in JPEG, does it mean, that it first handles it in TIFF and then converts down to JPEG for saving? Where does that downscaling process take place? In the operative memory? I have tried to see the differences in enlarged view, but obviously that needs some kind of dedicated software. NIH Image? Something more serious? And how does the compression algorithm look like (in the principle)? How does it "recover" data? According to which formula? Just curious. I can vaguely recall that some kind of compression system was an array conversion, while similar element arrays were stored as a multiplication factor of the original cell. Then backward coversion should not lose anything...? Anyway -- if I had RAW format available, no shutter lag and no pic-to-card-writing lag, enough memory space available, then I'd happily shoot RAW exclusively. When my memory card can store only 29 TIFF files, each of them being a serious task (taking all the breath away from that camera that is slow anyway), then it makes me feel as if I'm working with a view camera. Then I prefer my old MF manual beasts. It is anyway more pleasant to shoot film than digital, except digital saves me massively cash and time and feeds my curiosity of seeing the result immediately (OK - within an hour). Not being very serious about all that, Peeter
