Originally posted by jgnfld
I love my 16-85mm. It's on my KP 30-40% of the time. Didn't like it as much with my old K-50 as it really does require a sensor/recording system that can handle somewhat higher ISOs when you live somewhere as dark as Newfoundland often is even during midday. With the coming of my K-70 (which has finally just come back totally refurbished after my fall last summer which cracked the case) and now my KP I find it absolutely acceptable.
I also have a Sigma 17-50mm f2.8. It's great for people, ships, and buildings but my copy just does not render landscapes (at least here) well at all. Distance comes out looking very pointillist-looking rather than sharp and clear like my 16-85mm. I'd sell my Sigma except I do need it for indoors and outdoor shots like Christmas decorated fishing boats on a winter's night.
Since you have a KP, you should be absolutely satisfied with the possible exception of very dark or night conditions.
I find my Sigma 17-50/2.8 very good for landscapes, and just about everything else really. The 16-85mm does have more saturated colours though.