Originally posted by normhead Am I missing something, or has there been a bunch of bull poop passed off as fact on this and many other forums?
Yes, you are missing something key. Pentax lenses not being optically stabilized, user skills for tracking and beside speed of first focus, you are missing AF tracking speed of the camera algorithm.
My experience with Pentax K1 and DFA150450 or DFA70-200 or other DFA is the following:
- the speed of a full AF run from infinity to nearest focus (or vice versa) is way faster than the speed of most subject, with my DFA150450, focus from 100 meters to 2m is done is less than 0.5 sec (or less). that's about 200m/s = 447 miles per hour !
- when the subject motion is not straight or erratic, it is very hard for me to keep the subject inside the viewfinder under the zone of AF points, if I can't keep the subject steady enough in the view finder, the camera lose focus.
- usually, in AFC mode, the first shot is often in better focus than the two subsequent shots, which means that the camera is very fast to reach target and then fails to update focus fast enough is the subject motion is erratic.
I believe that if I completely miss shots because the subject is too fast for the Pentax AF, i'll also miss the same shot with a Canon or Nikon because my problem is my ability to keep the camera and lens pointed to the fast moving subject. It's only in intermediate situations that the Canon or Nikon will give me more keepers. So, yeah, Pentax AF is annoying as are other AF system.. and to take benefit of faster AF tracking of other brands will help in less than 10% of shooting situations. If I'd be doing only sports photos, then of course, a faster AF tracking would favor other brand vs Pentax. The thing is, having less keepers is not a big deal as I often have too many good photos, blurred shots make decisions to delete easier.