Originally posted by AfterPentax So my advise is that you take an AF lens and adjust the AF if necessary. After you have done that you manual lens will profit from the correction
That will only hold true if you use the APPLY ALL AF/FA menu. If you use the APPLY ONE menu to adjust one or more AF lenses, when you then mount a manual lens on the camera it will revert to whatever the APPLY ALL setting is....which may still be zero.
I know that not all Pentax DSLRs have the option to do a AF/FA both for individual lenses, and for a single global setting. For cameras that do both, the best practice is to do your adjustments for AF lenses individually, and then if needed make an adjustment to the global setting for manual lenses.