Not necessarily.... I think the reason why Pentax did set the default at ISO 200 is found in the D-Range Settings (menu one, first page). If you want to activate this feature (perhaps it's activated at default, I don't remember) the lowest ISO will be 200, because the camera needs the expanded range to correct highlights.
As I always shoot in RAW I don't see any advantage of this feature and so I didn't activate it. Required exposure corrections I like to do myself in LR instead of delegate to my camera...
Originally posted by Ryan Tischer From my experience there's virtually no difference in the noise I see between ISO 100 and ISO 200 on the 645D, ...
When I get my camera new I tried a lot of difference settings (you know, men and her new toy...
) and I found a visible difference in IQ Quality between ISO 100 and 200. Not much, but visible. I didn't checked this anymore but since then my standard ISO always is 100.
Originally posted by Ryan Tischer ?..but I read somewhere that the dynamic range is highest at ISO 200,...
See above...