Originally posted by deejjjaaaa you mean _2_ stops...
Right - two stops. Thanks for correcting that.
But the funny thing is, difference between 2 and 4 with the K20D isn't such a huge deal. I used to take a Sigma f/2.8 lens to weddings and graduations and such but I don't like the results as much as the results I get from the Pentax 16-45. So I shoot a lot at f/4, up the ISO, and the results are surprisingly good. I lose a stop going from f/2.8 to 4, but make it up in the body because the K20D's high ISO performance is about one stop better than the K10D's.*
As for the 35 f/2, I would like to be able to go wider occasionally. I tried using this lens to shoot indoor volleyball. I was able to increase my shutter speed a bit. But the loss of the zoom capability was too much to bear. So I don't use the 35 very often.
Will
*I hasten to add - in case anybody thinks I'm just nuts - that other things being equal I'd rather have faster lenses and I don't much want to buy anything that isn't f/2.8 or faster these days. But I've already got the Sigma 18-50 f/2.8 and can't afford to buy the new Pentax DA* counterpart, so for the moment I'm stuck.