At 10:33 AM 30/03/2006 , you wrote: > >Shel Belinkoff wrote: > >>This has been on my mind for a while. >> >>A TIFF made from a DSLR exposure is generally (always?) 8-bits. It's been >>adjusted in the camera and has been described as just a huge JPEG as far as >>results go. Camera generated TIFFs are huge. The TIFF generated by my >>4mpx Sony is 11+ mbs. >> >>RAW files are 12-bit, sometimes 14-bit, are supposed to contain ~all the >>captured data," often include a JPEG, as well as a bunch of metadata and >>EXIF information. The RAW file generated by the 6+ mpx Pentax istDS is >>generally about 10+ mbs. If the included JPEG is disappeared when the file >>is run through the DNG converter, the resulting RAW file is about 5 mbs. >> >>So, how is it that RAW files are smaller than TIFF files. This is doubly >>puzzling because it's been said that the Pentax RAW files are based on the >>TIFF format. > >Short version:] > >RAW files are 12-bits per color, but there's only one color per pixel >so there are only 12 bits per pixel. > >TIFF files are either 8-bits per color or 16 bits per color but with >three colors per pixel, so you get either 24 bits per pixel or 48 bits >per pixel. > >So TIFF files can be 2-4 times the size of RAW files of the same >image. (Both RAW and TIFF files can benefit from lossless compression, >so this ratio can vary ever further.)
TIFF is a very complex file format. Basically a wrapper used to contain digital info. Can contain RAW, Jpeg, Compressed, Uncompressed, 8 bit, 16 bit, multiple images and many other possible options. Powell
