Originally posted by lesmore49 I have a K1 and the 28-105, both of which I like very much. The 28-105 IMO punches above it's weight, but that also goes for the K1. The Sigma 85mm is a lens I haven't had much experience with, but I have seen other's results using this lens and I think you will enjoy this one, a lot.
The Sigma 85mm f/1.4 EX DG is an amazingly sharp lens. And this copy is pristine. I took one test shot with it of one of our cats when I received the camera. Auto everything just to verify things worked. Point and shoot. I pixel peeped on the image with as much zoom as allowed on the K-1 playback screen and the 3/4 view of the cat's eye remained incredibly sharp, cornea, iris & pupil.
All that said, I don't see myself using this lens enough to justify keeping it. I do little in terms of portraiture or studio shooting where this lens would shine. My biggest interest is scenic near and far, and to a lesser extent, wildlife. I will use the DFA 28-105 a lot. I have KA, F & FA (and a couple useable DA) lenses, to cover the subjects and focal lengths I would most use. What I could use more are decent AF FF lenses below 28mm and above 105mm. Don't be surprised to see the Sigma 85 show up in the market for sale or trade.