The lens that is on the K-3 70% of the time is a 70-200 Tamron followed by the current issue of the Pentax 50mm f1.8 prime. Agreed the 50 hunts a bit more than my other 2 lenses but part of that is I use it mostly for night shots and have use a flash light to focus it anyway.
I use exposure on the focus point and center spot focus with back button focus so the shutter buttion does not refocus. Shooting manual with flash or TAv usally with out it and always in RAW. You would think it be a very simple matter to focus on the eye closest to me, rotate the cam down to the rule of 3rds and fire.
Anything I am missing you think?