DA* AF problem - diagnostic opinions welcome
stan at stans-photography.info
Mon Oct 26 21:48:01 EDT 2009
The lens in question: DA* 300/4.
Basic symptom - it does not autofocus on my K20.
Expanded description - sometimes it works when first turned on, but
then refuses to work when woken up after a Sleep period.
"Doesn't work" = nothing happens. It is not mis-focusing, it is rather
doing nothing - no response to shutter depression or AF button.
Expanded description of "doesn't work" = not only will it not
autofocus, but I cannot manually focus either. Focus rings turns but
I tried another DA* lens (50-135) and it works flawlessly.
OK, simple issue, right? Lens needs repair.
So, when it isn't working, I switch the lens, on the lens barrel, to
MF. I still cannot focus!
So, I also switch the AF/MF switch on the body to MF, and then I
regain (manual) control.
All pretty definitive so far, it seems that it must be a lens problem,
and off to Pentax with it.
But when I use the same lens on a second K20, no problem. It works as
it is supposed to.
Dirty contacts on the lens and/or first body? I cleaned those; no
change in the lens (mis)behavior.
Any suggestions as to what is going on?
More information about the PDML