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  1. #21
    Jon Goodman's Avatar
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    If you have Canada Balsam (or any good and light rosin) and patience and time, you can re-cement your own lens elements and recolor the edges at the same time. Here's a tutorial I wrote a couple of years ago: http://www.fotomozaic.ro/artikel.php...21&idstory=412 I think I posted it here and at mflenses too, but can't be sure. As I've mentioned here and other places, I'm not a fan of UV cured cement. I've used that on watch crystals to set date windows and for other things. There are a couple of reasons I don't like it for lens repair, but to each his/her own.

    If questions, please contact me by email (jon_goodman@yahoo.com). I'm only seeing the computer every couple of days. I'm working on improving our attic (radiant barrier foil, duct sealing, additional insulation and trying to make sense out of an absolutely crazy maze of wiring up there).
    Jon

  2. #22
    JPD
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    Quote Originally Posted by pstake View Post
    I am not sure ... looks like lens separation and Jon seemed to think that's what it was.
    Only the rear lens group is cemented in a normal Tessar like yours, so you can be sure that it's just coating damage. It can look like lens separation due to the thin-film interference pattern that is common in both cases. In one case the thin film of canada balsam is separating, and in the other it's the antireflection coating.

    http://en.wikipedia.org/wiki/Thin-film_interference

    You said earlier: "
    Quote Originally Posted by pstake View Post
    There's some separation on the Tessar 45 on my ZI Contaflex II. Mr. Jon Goodman who frequently makes wry (and quite funny) comments on these forums, and who used to repair Contaflexes et. al, said that lens-separation is pretty common among these models.
    Mr. Goodman probably made a mistake about your Tessar, and thought of the Pro-Tessar auxiliary lenses for the later Contaflex models. They have cemented lens groups in the front.

    Jon, I know you are reading this!
    J. Patric DahlÚn

  3. #23
    Jon Goodman's Avatar
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    I had not stopped to remember about the front element to be honest. You're right however. The Teleskop and other auxillary lenses did have front cemented lens elements and were pretty notorious for separation. Hope all is well in Sweden.
    Jon

  4. #24
    JPD
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    Quote Originally Posted by Jon Goodman View Post
    Hope all is well in Sweden.
    At least my lenses look good. No signs of separation!

    However, the balsam in one of my lenses, a R▄O Iricentor (six elements in two groups) has turned slightly yellow, but it's even and there are no bubbles or separation (yet). It's a rare lens, so if it gets worse I might recement the components. I read your excellent article about recementing the other day.
    J. Patric DahlÚn

  5. #25
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    Well ... this is good news, I think. It hasn't affected image quality at all ... and the design of the Tessar with the sunken lens, it gives a small lens-hood effect, which should help if the coating keeps separating ... probably not much help for the OP so sorry about that!

  6. #26
    Jon Goodman's Avatar
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    If you need Canadian Balsam, contact me. I think I still have a little bit. I also have 3 grades of rosin...one I got from China which is very light and clear. I believe you can still buy Canadian Balsam from the Surplus Shed: http://www.surplusshed.com/
    Jon

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