Reviews and Problems with Sigma 17-70mm f2.8-4.5 DC Macro HSM
Showing 1-3 of 3
Decentering issues in two copies, third isn't as sharp as previous
K. Yee "kenyee", Amazon
2 January 2009
Summary: Maybe I just have bad luck w/ lenses :-P The first two copies had decentering issues (left or right half of frame was fuzzy) but only at specific focal lengths and ranges...it took a few vacations and lots of shooting to see these issues. The third copy I got from Sigma seems to be a bit softer than the previous two...and they swapped my serial# label from my old lens onto this one (the first time, I got an entirely new lens with a new serial#).
Summary: I returned the first lens because it was back-focusing with my Pentax K100D. The second lens was ok, but strangely, softer than the first one in tests with a focusing chart (albeit no backfocusing). Both lenses appear softer than the Pentax kit 18-55mm, which is disappointing. I decided to keep the lens as it is the only 17-70mm that works with K100D body, is not absolutely terrible, and is not very expensive. If you buy this lens, check for backfocusing problems.
If you get a good copy it's worth RRP, try before you buy
10 January 2009
Excerpt: When I first bought my Sigma 17-70 OS HSM DC for my Nikon D80 I couldn't wait to try it out at a wedding. The 2.8 aperture promised easy shooting at low light and I was expecting it to blow my plasticy 18-55 kit lens out of the water. The first thing I do with all my lenses is check accuracy of focus.