Originally posted by Alnjpn Is this (unreliable PD-AF) a K3 thing?
Er, from my experience it isn't. Coming from a K-7, I'd say, if anything, my K-3 is focusing faster and more decisively, particularly in low light (including situations where the K-7 wouldn't have been able to obtain focus at all). As far as focus accuracy is concerned, under good conditions, both are pretty spot-on, though they struggle, at varying degrees, with sophisticated tracking (haven't been able to test the PLM 55-300 yet, which is K-3 compatible and might offer some improvement). And although I haven't done any serious tests, in four and a half years of use, with a fair range of lenses, I've never felt a need to fine-tune my K-3 for front- or back-focus issues.
Therefore, my informal guess would be your issues are either due to sample variation or (perhaps more likely) dirt on the AF sensor.