Originally posted by Surovi I see what you mean. However the thing I find quite indicative is the time in seconds at 0 EV and -2 EV. You can compare them with the Nikon 7100 which does have faster performance than the K3 - see
Camera Test: Nikon D7100 | Popular Photography. And the roughly 200 milisecond difference is noticeable at 0 EV and -2 EV.
Another thing to take into consideration that often is not is how the lens affects the speed, reliability and consistency of the focus. For example although the new Sigma ART 18-35 1.8 is a fine, fine lens it can't reliably autofocus on at least the Pentax bodies. There are some lenses that work better than others and it doesn't really seem to make much difference whether its screw drive or HSM/DC/SDM. It seems more lens model dependent. In short, no matter the body or the speed of the focus its pretty much moot if you can't reliably hit the mark. Carrying this further, Olympus had this (accuracy) nailed with its Zuiko DSLR lens lineup. Rarely, if ever, did/do I get a miss (the E510/15-54 is very consistent as was the E30). But there is also less of a critical concern on DOF as well in the (u)4/3rds format. Currently (aside from the OVF/EVF arguments which I find get tiresome fast) Olympus (in part given the format in other part the excellent design and consistent quality) has the edge over many DSLR makers in accuracy (consistency and reliability) but likely not speed. Which is to be expected - Phase Detection is inherently quicker, Contract Detect inherently more accurate. I say "inherently" not to say Contrast Detect can't be developed to be quicker over today's Phase Detect systems - just that its easier to do something with one design than another, given the same investment of resources. Lastly we can talk more about tracking or burst shooting accuracy between the systems; but I digress.
Bottom line is that the K5 with all its known warts is as good or in my view better than the E5 in autofocus in anything but tungsten light and the K3 sees that bet and ante's up with a far more developed and capable system. It is quicker and far more reliable across a wide range of situations - given an appropriate lens choice (i.e. choose a current model lens like the Pentax 20-40 or 16-85 or 18-135 or Sigma 17-50, 17-70 if you are into zooms or the 40 2.8 or Sigma primes for example if you are into primes - there are other models in the Pentax lineup that would be recommended as there are in either Sigma's or Tamron's lineup - the point is you need to research the lens combo for you use case. The K3 would normally be expected to have a good AF as it would need to be, with 24 MP and a bit more sensitivity as a format to DOF than the E5.