Thanks, Toralf, I have skimmed that and bookmarked to read more closely. Getting a bit of an Ah-Ha from that skim, apparently folks are talking about electrons and holes as if they are the same thing. They definately are not. A hole is a space that can accept an electron, and if we are talking about 40K or so holes in the photodiode then that makes sense as that would be the amount of additional free electrons that the diode can accept (note that lots of them will bounce around and never find a hole to fit into). Still in the real world sense the output can not be considered stepped but a fairly smooth analog curve. Sometimes we try to apply too much to our understanding of things.
For those of you who insist that quantum mechanics apply at the real world level, please send me a quart of quantum foam, I want to use it as a battery. Reading too much SF lately <grin>. -- graywolf http://www.graywolfphoto.com http://webpages.charter.net/graywolf "Idiot Proof" <==> "Expert Proof" ----------------------------------- Toralf Lund wrote: >> So you are saying a 22 bit ADC is overkill. Wonder if Pentax knows that? >> > The marketing people probably don't know, or care; they only know they > can quote a higher number than the competitors. > > The engineers probably deliberately chose to have extra bits, so as to > avoid problems with accumulating round-off errors etc. in the processing > stages. >> BTW, Rob's explanation was clearer, but still not documented for my >> curiosity. >> > I'm not sure this can be considered an authoritative reference, but at > least it contains some actual numbers: > > http://micro.magnet.fsu.edu/primer/digitalimaging/concepts/dynamicrange.html > > - Toralf > > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
