Yes, I got a replacement from B&H and it has the same issue. But it is not as bad as the first one - just slight jumping, not noticeable most of time. I now realize this is common for this lens from what I observed and read online. So, I decide to keep it - image quality is top notch. However, the jumping makes me feel the lens is not top grade. As I said, this is the first Pentax lens I have this kind of behavior. I think the behavior is somewhat related to the manual focus ring design - maybe a clutch there have some play.
Last edited by hyyz; 01-07-2016 at 10:00 PM.