I wonder if I may "piggyback" on your thread here, Timmy? I too need to upgrade to something faster than the 18-55 f3.5 kit for the Pentax K10D that also has 1:1 macro for work (non-photographic;engineering parts). I have a Sigma 10-20 f4 so that focal length is covered. The sigma 24 - 70 would be OK that Ricktas mentioned. I'll check it out. Thanks