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.)
