Originally posted by Miguel That sounds bewildering. One way to discern whether the problem lies with your lens or the AF tweaking function is to borrow another Pentax AF lens. Run it through the paces.
Yeah, that's the problem right now; I only have the one lens but will likely buy my next one in a few days, the DA 12-24. I'll run the same tests on it. If I get the same AF results, I'll have narrowed the problem down to either me (i.e. test method) or the camera.
But one thing I didn't note in my original post is that this AF problem has occurred with real-world shots as well, where I took one with AF and it was slightly off whereas using MF with the exact same settings, composition, etc was bang-on in every case.
Anyhow, thanks for the good point.