This was posted in the thread
K100D battery life - Originally posted by Tom M I'm having a hard time believing you're getting better noise from the K100D vs the K10D - Are you using Firmware version 1.30 in the K10D?
I've seen ISO 3200 shots from a K100D and it seemed like a last ditch effort to use.. So, all things being equal, the K10D at 1600 seemed far better than the K100D at 1600..
Just my expereience so, don't go shooting me.
- since it seemed out of place in that thread - I thought I'd respond in a thread with a more appropriate title.
In theory for the same sized sensor the more pixels, the smaller each photo site/pixel -
and smaller photo sites usually give higher noise (or lower signal to noise ratio).
However this is not quite linear or straight forward.
The more pixels - the more effective the noise reduction -
simply because there is more information to play with.
I took the samples from the reputed reviews of the Pentax K10D and K100D -
dpReview and
dcResource Page, and placed them side-by-side so that comparison would be easier -
dpReview samples showing noise -
dcResource Page - noise samples -
Looking at these side-by-side - K10D's ISO1600 looks less noisy than the K100D's ISO3200 -
but to me the K100D ISO1600 looks better than the K10D's.
The K10D does do a creditable job on its ISO1600 -
but one can see the softening due to the noise reduction -
whereas I think the K100D does a better job in its balance in retaining detail/definition.