Problem with extension tubes

Hi all,

I have a set of AICO extension tubes which I have had for many years and have been used on my original MX, the K10D, the K20D... They don't have A-type contacts but do have the actuation lever so that setting the "allow use of aperture ring" setting works fine. I've often used them with lenses like my M100/2.8.

I've just been trying them with my K-3 and my K85/1.8. The aperture doesn't shut down when I take the shot. Yes, allow use of aperture ring is set to yes. Any clues as to the problem?

Thanks, Kris.

Guess:
Your extension tubes are non conducting (black paint or anodized); try to stick some foil between the tube and the camera body to sort the contacts.

Hi Kris,

If as sterretje suggests it is due to the black paint than you might want to remove a section close to the contacts area. This is what I had to do with my Petri 28/2.0. The aluminium foil trick does work, but if it bunched up or rips you run the risk of little bits of foil inside your camera

Here's where I scraped on the back of the Petri:



Alternatively you could buy a set with contacts and modification from me - I'll do you a good price

I had similar problems with black painted ones and, having scraped the paint off, it still didn't work so I tried some of that very expensive real silver paint - absolute waste of money - don't do it.
I had another set with full contacts that refused to work which had an extra pin (Richo style). I opened the base and removed it from each tube ( fiddly, awkward job) and hey - it now works! No idea why.