[gaweidert]

Have you tried to do a complete reset back to default settings?

[UncleVanya]

The contacts look fine. I'm stumped. I don't have a Ks-2 to check my 18-135 on. I am sorry.

[Rabbit48]

One correction: interestingly, the camera does actually take pictures while in the spot focus/multi-focus frenzy; it also appears to try to auto-focus, even though the display shows MF mode.

[Rabbit48]

Unfortunately, the reset to default settings did not change the behavior. I now also believe that this is an electrical contact issue, since both camera body and 18-135 lens work properly in different environments. Perhaps this body and this lens both fall at the wrong end of their respective tolerance ranges for proper physical electrical contact (??).

[pentasonic49]

Do you have a friendly Pentax dealer, or friend with SDM or DC lens to try out?

[Regi]

I didn't post anything because nothing works and I finally sent it to camera precision, it will be in my hand in one or two weeks.

In my personal research I found that all the screwdrive lenses (SDM) works fine, but with the DC motor the camera goes crazy. I tested with two differentes 18-135, that by the way, works fine in other pentax body (so is discarded that the problem is the lens).

I hope that camera precision say me something about the error, at least was cover under warranty the reparation.

When the camera arrives I will post if it get fixed or not.

[Rabbit48]

Thanks for the update, Regi. Of course, the 18-50 kit lens that came with my K-s2 is a DC lens and it works, so it must not be as simple as DC vs. SDM. Also, B&H (for example) sells the K-s2 with the 18-135 lens as a package. I'm anxiously awaiting your post when you get your camera back.