This might be interresting, please discuss.
Sent my K-7 for adjustment, Pentax service claims it was only a tiny bit off, sure... I still get very inconsequent results. I got the feeling they aren't very professional (kameraservice.se swedish pentax repair). They use a DA* 55 1,4 and focuses at one single point when adjusting.
According to dpreview the 55 1,4 AF behaves differently on different cameras (cameras that are all working correctly with FA 50). *(See quote at the bottom). Because of this I don't trust Pentax service to adjust my camera correctly. If the lens behaves different on different cameras there must be a bigger problem with Pentax AF. Also the 55 got spherical abbrations (focus shift), this can NOT be the correct way of adjusting focus on a camera.
I got the feeling my gear can't be perfectly adjusted. Feels good man (sarcasm).
My K-7 focuses OK at best, got it adjusted. My K-5 is a nightmare. Going to send it in ASAP.
I wish they'd buy the EOS 350d AF system to the new K-5 (joke). It got a LAZER thin center point with amazing accuracy and speed. Gotta love it. Tried to shoot on a specific straw on a flower and it nailed focus on the spot. The k5/7-basketball center point sets AF randomly.
Sorry, I'm really pissed off.
Why does some people get perfect results with any lens? What are they doing? Are they some kind of super photographers? Why can't I get it right?
"(using test bodies which had no such problem with the smc FA 50mm F1.4). On our K20D the lens back-focused considerably, and required the maximum correction of +10 to function properly. On the K2000 the lens front-focused, and due to the lack of AF adjustment we were unable to achieve consistently accurate focus by any means. We got the best results on Pentax's latest model, the K-7, but the lens still front-focused slightly and, while many pictures turned out acceptably, it needed an adjustment of -3 for best results." Pentax SMC DA* 55mm F1.4 SDM Lens Review: 3. Test results: Digital Photography Review