Originally posted by Lowell Goudge Is it different with the TC and lens when not mounted? Maybe the AF screw drive is getting caught and not releasing
The TC has no way to disengage its own screw-drive pass-through mechanism and that is not a quick-shift lens -- if the focus ring is moving, the screw-drive is moving. So yes if you take it off the body but with TC attached to lens it should be easy to see that the screw is spinning on the TC when you turn focus ring. I've got the same lens (Pentax version) and noticed the same thing on my TC that has screw-drive pass-through...