DA35 f2.4 & extension tubes

For the recent weekly competition I had intended using the above combination (Jessops tubes with the contacts) but found the lens would not stop down at all. I discovered that with the lens and tube off the camera the actuator arm in the extension tube wouldn't budge at all. With the Pentax F 55mm f1.7 there was no problem at all and I cant see any difference between the two lenses in this respect.

Any ideas?

Mine will not work either.

Just tried my DA35 on some vivitar tubes all ok, just plain tubes though no contacts through, still waiting for those to be delivered.

Possibly the plastic mount... you may have to short
a couple of pins out with silver foil.

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Algi, it isn't an electrical problem but a mechanical one. The linkage in the tube is just a floating piece of metal that should be pushed up and down by the actuator in the mirror box and then allowing the iris to close to the desired f stop. The linkage in the tube seems to be jamming somewhere with the lens.

I will try some other lenses tomorrow because this is the first time, I think, I've used a DA lens with those tubes.

Sorry. possibly mechanical, but might need the contacts, which
it seems to have anyway

I've just tried 3 sets of tubes on my DA35 f/2.4 and 2 sets
(Aico and Jessop ) won't even screw on the lens. The camera's
a K-5 and they screw on that OK.

The 3rd set Triplus Pz-AF ( the Rolls-Royce of ET's
with 8 contacts) fit like a glove. Open Ap. Metering works
electrically, so it doesn't need to stop down and I fired
off a shot which was perfectly exposed at f/5.6. So it seems
to be down to the tubes and I'm sure you will need the
scraped contact.

I'm surprised they screwed on in the 1st place

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Contact scraped ages ago, the curiosity is that they work perfectly with the 55 but jam with the 35. As far as fitting onto the camera and lens in the bayonet sense there is no problem at all.

Something to do with the lack of aperture ring (and as such the lack of 'A' setting) on DA lenses perhaps?

No, definitely a mechanical problem

Exactly my point - The DA lenses are different mechanically than A/F/FA lenses as they lack an Aperture ring and the 'A' setting (and its coupling)

All the other DA lenses work perfectly as I would have expected, it is just the 35mm as Geordie01 has found as well.

Just tried the DA35 lens on the jessops auto tubes that arrived this morning all working fine and dandy.

Now just to practice a bit.

That would seem to point at my 35mm lens perhaps as being some how different from normal.

I am thinking that the plastic bayonet mount may be slightly thicker as the lens is a really tight fit on the tubes and requires more force to mount it
and the aperture lever is then very stiff.

That's interesting I'll check mine and let you know.

Never mind, it'll soon wear down