9 out of 10 points and recommendedVery good build quality Manual focus over rideJust a little corner softness
Bought my copy new in 2010 from B&H just before they went out of stock.reviewed January 4th, 2015
Would have liked the Pentax 50 -135mm but that was just too expensive in New Zealand.
Also worried about the reported SDM failure rate with the Pentax.
Unlike the tested copy here, mine is almost perfect at 50mm straight from F2.8 (as good as my Pentax A50 F1.7mm prime).
Progressively softens off towards the top right hand corner as it is zoomed out.
Worst at 150mm but still correctable by stopping down to F8.
From 70mm to 100mm, F5.6 - F6.7 is needed to sharpen up the corner.
However centre sharpness at F2.8 at all zoom lengths is very good, very useable.
CA is minor at all zoom settings and correctable in raw software. (I always shoot raw)
Distortion is also minor and correctable.
Used on 4 different bodies but now lives permanently on a K30 - no focusing issues at all on that body.
Fast, silent, reliable and almost 100% accurate.
I have been very satisfied with this lens. It's a great street lens.
I agree with Andrews caveat -- make sure you have a good copy before you buy.