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01-15-2010, 12:55 PM   #1
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M42 Voigtlander 90 Aperture Pin Problem

Any ideas on how to keep the aperture pin depressed on a Voigtlander 90/3.5 m42 lens besides removing the mount? I stripped one of the screws so that method is not an option currently. I was planning to attach a piece of Q-tip inside the mount to hold it in place, but stripped the screw in the process.
This lens will not stop down unlesss the aperture pin is depressed.

It looks like the in body Pentax m42 adapter will keep the pin depressed. Can someone who has one confirm? Ideally I'd like to be able to use it on both my Pentax and Canon cameras. The Canon adapters don't appear to cover the pin like the Pentax mount does.


Last edited by Sirfishalot; 01-15-2010 at 01:01 PM.
01-15-2010, 01:13 PM   #2
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Jay, you may have that backward - the Pentax K adapter does not hold the pin in. I'm thinking (though don't know) the Canon adapter may hold the pin in.

There is a Chinese made K adapter that holds the pin in, however this one suffers from the failing common to all non Pentax adapters - the thing will continue to rotate in the K mount... A bit of Dremelling will fix this, I understand. (reminds me: I need to do this)
01-15-2010, 01:20 PM   #3

I need to dremell mine too...

The pentax in body adaptor will not hold the pin in... As Nester says there is a chinese knock-off that is designed to push the pin in with a ridge on the inside edge. But it does spin do to a slight mess up on the machining. There is a thread at showing the little bit of metal that needs to be removed to get it to lock.

If it is an expensive lens, I would try and get one of those, if not... a tiny dab of super glue works. I am not recommending this, try at your own risk... The whole thing could blow up.
01-15-2010, 01:47 PM   #4
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I don't know about the Apo-Lanthar, but I know that with my old Voigtländer Color-Ultron 50/1.8, I can just depress the pin far enough and to the side so that it would catch the ledge and stay put. You can also try taking the mount off (M42s are wicked simply constructed so I don't think you need to worry about reassembling) and take the spring mechanism off to keep the pin semi-permanently depressed.

The Chinese M42 adapter works, too, even without dremeling, so long as you take care not to turn the lens too much.

01-15-2010, 02:33 PM   #5

That is a good point

on some of my old m42s with pins... If you push the pin in with something past the lip it will lock up...

And excuse me for some bad advice, if it is a lanther we are talking about... no way put the glue on it!!!

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