I did not see this lens in the archive so I thought I would post my first impressions. This is NOT a review. I am just sharing my first shots from the lens and letting you be the judge.
Here are the details. First this lens gets confused for several other Sigma lenses. There is a 17-50 and an 18-50 with a fixed 2.8. This lens has a variable f-stop from 2.8 to 4.5. It is a crop sensor lens, with OC (4 stops) and with HSM. It clearly is not the top of the line HSM. It is a little loud (for HSM) but not in real world conditions. I paid $189 shipped.. new. I got it to gain some lens speed, faster focusing and wider everyday lens and OC for more flexibility. My goal is to find a birthday party and Disney World lens. For a snapshot lens I think it has the potential to be very good. (I do not, and never did own the kit lens, so I cannot compare)
The lighting on these samples is poor (intentionally). It was late evening and almost all of the pictures are in the shade of the setting sun. All shots are unedited unless noted.
NOTE: I accidentialy took these at ISO 800.. they are a little grainy.
Handheld @ 1/5th of a second 45mm (a borderline keeper, but also the second photo I took after taking the lens out of the box.)
Flower shot for detail