dbump wrote:
Tim, definitely (though there are non-lossy tiff compressions, I believe). I meant that the computed uncompressed size of the jpeg should be the same as the actual size of an 8 bit tiff from the same camera. It's just that you never really have to deal with the 'uncompressed' size of a jpeg, practically speaking.
I can't say I agree with that totally, but I can see where you're coming from. TIFF is lossless, JPG is lossy, so you're comparing apples with oranges. Perhaps when you load them in photoshop it will take up the same about of memory for each, since there's the same number of pixels and bits per pixel. The TIFF has quite a lot more information so should always be larger. I don't know of any Canon camera that outputs TIFFs, perhaps the 1 series do but I doubt it - too inefficient.
If you have RSE generate a TIFF and a JPG i'd expect the TIFF to be much larger maybe 5 times, maybe 10 times, can't really say since I don't really use TIFF, I use PSD and JPG.