I always use center point when shooting boat racing. Backgrounds are too busy to do otherwise. This and the other shot I posted where using my DA* 60-250 with the Pentax HD 1.4x teleconverter then cropped on top of that. I've been real happy with the auto focus with that combo on my K-3. It took some figuring out at first. This shot is f8, 1/1600, 640 ISO. DOF with the teleconverter is definitely narrower than without. Still need to play some more this spring to find the sweet spot. The Pentax T/C was definitely worth the extra $$$. It communicates properly with the camera and takes some of the guesswork out of things.