TIFF is essentially a container format only defining the wrapper around
the actual data, but there is a 'standard' format for 8 or 16bit image
data inside which is extremely inefficient. RAW files typically use the
container format, but lack a lot of the extra baggage of the internal
image format. DS/DL RAW files use a packed pixel storage method so that
12bits of image data takes up only 12 bits of space, the D pads the data
to 16 bits with 0's(hence the almost TIFF-sized D RAWs).
-Adam
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.
Shel
