Originally posted by Jeff Thanks for your thoughts. It does seem that the K-5 (in either ii or iis form) is indeed enough.
Between my K5 and K5ii, the AF is definitely different on the K5ii: of course I'm sure the tungsten light issue was addressed and the sensitivity is higher. But it's still not what it needs to be; by that I mean that my f2.8 lenses either:
1. require more than the sadly insufficient +/-10 adjustment range (Pentax and 3rd party - even * lenses - both new and used);
2. can't be adjusted for both ends of the focal length range;
3. can't be adjusted for every subject distance (all my prime f2.8 lenses are macros, so maybe a bigger challenge than other primes.)
But CDAF is pretty good with any K5, original or ii variety. I should have said it before but the other huge leap I got with the K5 was having live view for the first time, and thus the more accurate AF capability. I was pretty happy with PDAF with all my cameras honestly when I only used small apertures, which is still a high percentage of my photos. Using longer lenses at larger apertures is what made me realize the shortcomings of the PDAF implementations.
Anyway I'd pay a premium - but only a very small one - for a K5ii vs. K5. Generally I find the premiums for the ii versions, especially the iis, more than I could justify, unless maybe I could test the camera with a lens I wanted to use and found it could give me the PDAF results that I needed in lighting conditions were an older K5 wouldn't be likely to focus accurately.