Many thanks to each and everyone who responded to my question.
Much appreciated!
Individual responses below:
Originally posted by Adam Yup it should still work, just make sure they're focused to infinity.
Yeah, getting the lens focus in the right ball park isn't the issue. The camera just doesn't attempt to focus at all if I mount a non-A lens on the adapter.
I reckon it has to do with overall conductivity problems.
The chip inside the adapter could be toast, but I don't think so as these things are rather robust.
Originally posted by BillM Cant check mine currently,60 ohms flange to flange does seem bit odd.
There is a spring-loaded rod connecting the two flanges and at the spring side the backside of the flange seems to be a bit dirty. I'll try to clean it well and that should help with lowering the resistance.
Originally posted by BillM Have you been able to determine that apeture coupling with "M" len(s)
stacked on AF is good to go.If those linkages are 'sticky',could be trying AF while not stopped down,in that case,might not be enough light/contrast to do so.
The mechanical aperture coupling works fine. Lenses stop down as they should (with optical preview and during shots).
Originally posted by steve1307 I haven't tried this but with an M42- PK adapter you need a piece of foil on the contacts for it to work.
Is that because the M42-PK adapter does not short any of the contacts?
Originally posted by steve1307 You can also disable the AF of the adapter by taping over the contacts to the camera so you can use it just a a passive 1.7x converter for "Catch-in-Focus" with any lens.
Thanks for the hint. At the moment I'd love to get the AF going for non-A lenses. I think I'll get it to work one way or the other even if it means to permanently short one of the adapter contacts.
Originally posted by steve1307 When I get home in about 7 hours can test on an M lens and a multimeter.
I'd be interested in your reading.
Originally posted by steve1307 The archived manual ( 1987 poorly scanned copy) is on the pentax website.
Wow, thanks heaps!
Originally posted by Canada_Rockies The F stop with M lenses is invisible to the DSLR's because the KAF-3 mount dropped the mechanical follower.
Sure, my problem is that the AF doesn't work with M lenses. I'm optimistic, though, that I'll get it to work.
Originally posted by SOldBear This is how my Pentax 1.7X AFA behaves with my K-7 and K10D:
Thanks for the list! It is consistent with what I observed (and what the manual says).
Originally posted by SOldBear If I use a piece of Scotch tape to cover the contacts of the AFA (between the AFA and the lens), the combo doesn't focus at all. This can be the symptom that the OP observed. The lens may have a painted (or anodized) mount.
I tried several manual lenses and none of them worked. Would be odd if the mount of all of them would not be conductive. But I'll try to use a piece of foil just to make sure.