Godfrey DiGiorgi wrote: > On Jul 5, 2006, at 3:20 AM, Toralf Lund wrote: > > >> But, but, isn't a similar trick available for digital? Can't you just >> reduce the gain a bit and try to get an exposure "in the middle" (with >> the same exposure) rather than aiming for an exposure "to the right" >> (with a somewhat higher gain setting)? >> > > If you understood what I already wrote , Sorry, apparently I didn't look at the post with proper explanation earlier. I think I've found it now?
So, essentially what you are saying is that you want to retain the data "exposed to the right" past the gain phase because that can only scale the values in a linear fashion, while the RAW conversion is non-linear? (And non-linear in such a fashion that an input where the low-range of values are "stretched" is advantageous.) > or the LL article, I don't think that explains the above distinction very well, and it seems to be talking mainly about signal-to-noise ratio, which is a somewhat different consideration from the one you mention. One minor point, though: Do you actually know that the CCD has 4096 different values? I mean, the A/D gives you that, and you obviously expect that to be matched to the CCD, but I've been thinking that it may make sense (partly due to the gain etc. involved) to keep the sensor resolution slightly higher that the one of the A/D. If it is set up like that, obviously you want to do as much of the scaling/"exposure correction" as you can in the analogue domain, as you'll retain more of the dynamics in the digital output that way... - Toralf -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
