Originally Posted by
soulman
From what I understand, most if not all RAW files are already compressed. I just zipped a 38.4MB RAW (Canon CR2) and the ZIP saved only 900K. Another test on a 41.4MB file saved 1.1MB, so we're looking at around 2-2.5% which could be useful but isn't a big deal. On the other hand, a 126MB uncompressed TIFF ends up as 41.5MB, so I think we can be pretty confident that the RAW files are compressed already. And yes, there is no degradation in image quality - ZIP and all the other archive formats are lossless.