Summary: Spectacular lens. Extremely sharp on the Pentax 645Z, great contrast, and small footprint. Great grip. Little to no flare, even shooting directly into the sun. Only minor quibble is that there is some purple fringing against bright light. Fantastic value.
Excerpt: This lens is so great in every way. First it has a very useful 43mm equiv. format, it fits in the middle of two traditional 'normal lens' 35mm and 50mm, you just put anything on frame and get no distortion of any kind. Second, its so sharp! Seriously no one can complain about this!
Pros: Consistent Output, Durable, Fast / accurate auto-focus, Weather sealed
Excerpt: I gave 8 because of the sharpness decrease at corners when I focus at infinite (see below for detail). Other than that, this lens is really good. I would recommend this lens except those who frequently focus at infinite.
Excerpt: wow, I was not prepared to be so impressed with this lens. Everything about it seems to be well considered and executed. Sharpness is wonderful as is bokeh and contrast. The 9-blades make lovely 18-pt stars too.