Pentacon 1.8/50

[montecarlo]

Hello everyone,

Here is a link with a Pentacon 1.8/50 lens dismantle (for diaphragm cleaning, in this case):
http://www.dughir.ro/articles.php?article=./articles/article00002.html

It might help.

Good luck.

[LucisPictor]

Hi and welcome to the MFL forum!

Thanks for the link.

Carsten

[Orio]

THanks Montecarlo, I personally will never have the nerve to dismantle one of my lenses this way, but thanks anyway, these are useful resources!

[bob955i]

C'mon Orio, you haven't lived until you've dismantled and possibly destroyed at least one lens - the more expensive the better......

Think of it as character building.....

[|||Por|||]

Thank you very much.

I am having the same problem of sticking diaphragm blades and this helps a lot.

[Attila]

Very nice avatar! Nice to see you here!

[patrickh]

Hats off to a brave man. I would have neither the nerve nor the talent to do what that guy did. Thanks for the link

[sirslak]

I have a question involving this post. But first let me say: what a lucky coincidence to find this post, thanks so much!

To tell the strange story: yesterday I bought this very same lens for only €7,50 (auto revuenon 50mm 1. which had a very interesting story!

The seller didn't use it anymore, but he worked at ASML, world's leading lithography chip machine manufacturer. There they wanted to test a coating for IR absorbance. So they send this lens to a 'befriended company' Carl Zeiss for a metal vapor coating.
In the spirit of maintaining good relations Carl Zeiss offered AMSL to optically correct the lens as well. And so they did.
Although Carl Zeiss was impressed by this old beasts IQ (or they said maybe because they attributed to it in the past, if I am correct), they made the lens perform well above factory standards after the correction (this guy talked about 0.1 - 0.2 pct. aberration). Great!

I didn't know much about M42 mounts, only K-mount, so after a better inspection at home I found out that the aperture has oily blades, but still works, only slowly.

Too make it short: does anybody know the whole story about lens correction?
Which optical elements are twisted, turned or tilted w.r.t. to which mechanical lens elements?
Which of the steps from the posted website ruin the alignment of optical elements, which do not?

Should I clean the aperture (I have a technical background...) only partly from the backside, completely from the frontside, or not at all?

Thanks so much for sharing your knowledge!

[Attila]

Welcome to aboard! I hope somebody able to answer for your post soon!