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pentacon MC 50mm 1.8 fix loose barrel
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PostPosted: Tue Feb 26, 2019 1:24 am    Post subject: pentacon MC 50mm 1.8 fix loose barrel Reply with quote

Hi, I need help with this lens, the inside barrel is sort of loosened. So , maintaining the outer barrel by hand ,the inner one it's got a little play , the mount is M42 . I assume it shouldn't be a big deal,but after using the Helios the other day, I was going to take for a walk the pentacon and I don't like loosened things in the lenses.


PostPosted: Mon May 13, 2019 1:44 am    Post subject: Reply with quote

I have the same lens in Praktica mount, and it has the same issue.

The version I has is dismountable from the bottom. You need to take off the plastic "cover" from the mount (just carefully pushing it off) and to get reach to the retaining screws. Once you unscrew them and the mount is off, you'll have access to the inner ring where the attachments might be tightened without the further disassembly. In my case I could not get off the mount because one of the four screws found itself just dead fixed. I completely erased its head with a screwdriver, with no effect. But I could see the loosened connectors through the hole.

If the construction of your lens is the same, and your screws unscrew, you may fix the issue.


PostPosted: Wed May 15, 2019 7:05 pm    Post subject: Reply with quote

Thanks for your answer. The M42 mount it's got 3 screws on the mount, I've never taken out one yet, is it safe to remove the mount by unscrewing those 3 screws? In nikkor I've had no troubles , but Canon nFD was a pain in the.....to put it3 back


PostPosted: Wed May 15, 2019 7:07 pm    Post subject: Reply with quote

The mount is all metal,no plastic cover at all, at least on the outside....


PostPosted: Thu May 16, 2019 7:47 pm    Post subject: Reply with quote

This should help. Although this is the Early model,a rebadged meyer Optik.
https://www.youtube.com/watch?v=I-06BGrA6Bo


PostPosted: Fri May 17, 2019 3:10 am    Post subject: Reply with quote

A very instructive video, Eddie, thank you!

Kiddo, from your words and from the above video I conclude that mechanically the Prakticar version is a completely different lens. But the M42 version seems easier to dis- and reassemble. Good luck with your reparation!


PostPosted: Fri May 17, 2019 5:06 pm    Post subject: Reply with quote

Thanks for the video, I've opened it up, and when I've got up to the inner side ring which sits on top of the blades, there weren't the 3 screws to remove that ring, only 3 centers which helps the ring to sit on top of the 3 bolts, so I asume that ring it's been glued on top of the helical. I assume that the problem with the front group, might be underneath of the front Name ring ,so probably there are some screws underneath,but right now can't take it out.