Focus Calibrations for (Pentax) (D)SLR Bodies and Lenses

From time to time, there exist DSLR users report about different AF issues, regardless of brand. Nevertheless, the fact is that some particular DSLR or lens models are being reported by more users than the others. It is just because either that those particular models are indeed less accurate or simply that they are more popular (so that there are more users to report, by proportion) or both.For