Pentacon Prakticar 1.8/50 first version aperture control

[iangreenhalgh1]

Hi folks

I wanted to convert this lens to Sony A mount, so I removed the mount and the back of the lens, then removed the aperture lever and the electrical contacts then put it back together, minus the mount.

Everything works aside from an annoying issue with the aperture.

if you close the aperture, it doesn't do anything unless you use a pointy object to push the aperture arm inside the back of the lens anti-clockwise. Going the otherway, from closed to open, it works as it should.

I thought I could just jam the arm into not moving from the position it is at when the aperture is closed, but this doesn't work, the arm had to be able to move.

So what can I do to rectify this issue? It's like there should be a spring to return the arm but it's missing.

[RSalles]

Ian,

If you feel that there was an spring where it's not now, try with a tiny elastic (we call this here "elastricot" and use it here to attach little bait to hook for fishing).
If it works as intended, time to visit the lens tech or the watch repairman for searching for a tiny spring,

Renato

[iangreenhalgh1]

I'm just not sure what's wrong, I compared it to my other copy and without taking it apart to compare, I just haven't got a clue what is wrong.

Oh well, it might have to go off to a pro to be fixed.

[RSalles]

If you're not in a hurry and are in love with this copy you can send it to me and I'll try to fix it for you - for free, of course,

Cheers,

Renato

[philslizzy]

You can buy a chipped adapter (infinity focus) for less than £10 post paid.