Originally posted by ChristianRock The pre-C version of the Sigma 17-70 was also HSM and was also f/2.8-4 (yours, I believe, was f/2.8-4.5)
That's correct. I actually sought out the screwdrive version so I could use it with my old 6 mpx bodies. I acquired a super clean copy from member SpecialK. It's a solid lens and a bit front-heavy, but still very manageable. Very sharp from wide open with a useful pseudo-macro mode. It doesn't have the Pentax colors but that can be mostly remedied in post. btw, I recently purchased a very clean used DA16-45/4. Really nice and 16mm is very handy! I have to admit not being totally blown away, however. I think I was a bit spoiled having an exceptional copy of the 18-55 kit lens! But the 16-45 will be getting plenty of use
Oh, and like you, I'm firmly entrenched in aps-c land.
Here's Doc with the 17-70 DC macro, at f/3.5: