Summary: I was greatly anticipating trying this lens after all the stellar reviews. However, my lens was awful. I'm not knocking Pentax because my other lens is fantastic; I just received a bad one. When looking through the viewfinder, there was like a gray gauze across the entire lens and it was very dark. It wouldn't work correctly in autofocus. The image was mediocre. I returned it to Amazon yesterday right after I took it out of the package and tried to use it.
Summary: First of all I am a retired professional photographer who has made a living from selling my photos for many decades, I'm not a Pentax basher or a Nikon or Canon lover, I assure you. I have owned and used many brands. I'm sure however my honest review, which is my opinion of this lens based on the sample I had will attract 50 negative comments about myself because I rate this lens one star.