John Francis wrote: > On Thu, Jun 15, 2006 at 02:09:02PM -0700, keith_w wrote: >> The image captured as a tiff or a jpeg is converted by the camera's internal >> firmware (I suppose ?) to be what it is. Same with RAW. >> >> Any losses that occur to any image captured and saved happen after the >> photog >> grabs hold of the image and messes around with it!
> Not really. The original capture, as registered on the sensor, > has 12-bit data. That level of precision is retained in a RAW > file, but in a TIFF or JPEG low-order bits are thrown away. > It's not quite as simple as saying "the bottom-most four bits > are lost", because there are also some non-linear processing > steps involved, but there is no way to store twelve bits of > information in only eight bits. Okay. Re TIFF images, my manual says the tiff images are non-compressed. That's just a gratuitous comment, as I don't know that much about tiff images, except that they are way too large! <grin> But, by definition, jpegs are always compressed, from a little bit to a lot, depending on the file size you set. I had not addressed that truth in my previous statement because I was thinking of how a jpeg image increasingly deteriorates the more times you manipulate the image and save it. So, my mind got stuck on that aspect of it. You're right, of course. Thanks, keith -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
