Originally posted by Rondec I think Pentax auto focus is actually pretty good with any DC motor or ring motor driven lenses which include the DFA 24-70/70-200/150-450/50/28-105, as well as the DA 18-135/16-85/20-40.
The 55-300 PLM is probably a little faster than those others, but plenty of the people commenting in this thread are still using SDM or screw driven lenses, both of which are not perfect with respect to auto focus.
I doubt Pentax AF.c is ever going to be all that good. But I rarely have opportunity to even use AF.c and most of the time when I do, it works for me. I don't shoot in gyms, or indoors a whole lot. I have many images of my dogs playing in parks taken with APS-c that had keeper rates way above what the more critical posters on the forum do. But long story short, the only reason I ever shoot AF.c is to find out what all the fuss is about, and it's never as bad as some on the forum claim it is. And with BiFs, the camera has worked for me flawlessly for me when I kept the bird in the viewfinder. I can think of 3 occasions in 01 years where I even used it.
Simple fact, I'm guessing of the 120,000 images taken with my K-3 less than 200 were taken using AF.c IN other words, Pentax AF sucks, based on AF.c performance is completely irrelevant to me. with my dogs, my keeper rate is over 80% I get the images I want. What's the big deal?
I find it incredible that people go on and on about how bad Pentax AF.c is, with no understanding of how irrelevant that is to my shooting, and I would expect most Pentax users shooting. I look though flickr images and I can tell you, there are a lot of other shooters out there for whom it's also irrelevant. SO here's why the whole Pentax AF.c sucks thing is nonsense for me. What Pentax AF is lower than average for, I rarely do. I would call people warning people like me not to buy Pentax because of AF.c performance irresponsible.
People make big deal out of a function I use .17 percent of the time. Translationn 1.7 shots per thousand. And when I do use it I have about an 60%-80% keeper rate. This is probably the most over blown deficiency in a camera ever, at least for me. (Please spare me, the "not everyone is you nonsense". Everyone may not be like me, but an awful lot are.) And completely bogus for all but a few.
Honestly, I'll take an OVF with IBIS over what else I see from other brands any day. I use IBIS every day. I use AF.c once or twice a year. People really need to get grip, to understand the fact that they have point with Pentax AF.c doesn't make it relevant to most shooters. For the most part they are looking at a very small picture, and ignoring the big picture. The big picture for myself and i suspect a lot of others make a difference in 2 images per thousand. That's pretty irrelevant by any estimation.