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Thread: Question: What is this?

  1. #1

    Join Date
    Jun 2015
    Posts
    49

    Question: What is this?

    I acquired these LR lenses and would like some info on what this ring is on the rear elements. Also, what should I do about them?

    Thanks

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  2. #2

    Join Date
    Feb 2008
    Location
    The Highlands of Scotland
    Posts
    322

    Re: Question: What is this?

    Looks like balsam separation between the elements.

    Very little you can do about it.

    Mike

  3. #3

    Join Date
    Dec 2018
    Posts
    710

    Re: Question: What is this?

    Are those Rodenstock Sironars? (plain Sironar, not -N)?
    There was a problem with separation with early ones, due to adhesive.
    Not much can be done about it...try 'em out, see what you get.

  4. #4

    Join Date
    Jun 2015
    Posts
    49

    Re: Question: What is this?

    Figures, thanks

  5. #5

    Join Date
    Jun 2015
    Posts
    49

    Re: Question: What is this?

    Oh well, thanks.

  6. #6

    Join Date
    Sep 2014
    Location
    North Dakota
    Posts
    1,186

    Re: Question: What is this?

    Maybe you can sell them to Sally Mann? ;-)
    Last edited by Willie; 25-Dec-2021 at 07:42.
    "My forumla for successful printing remains ordinary chemicals, an ordinary enlarger, music, a bottle of scotch - and stubbornness." W. Eugene Smith

  7. #7
    Nicholas O. Lindan
    Join Date
    May 2006
    Location
    Cleveland, Ohio
    Posts
    333

    Re: Question: What is this?

    At f22 they may work just fine. As Dugan suggested, try them out.
    Darkroom Automation / Cleveland Engineering Design, LLC
    f-Stop Timers & Enlarging meters http://www.darkroomautomation.com/da-main.htm

  8. #8

    Join Date
    Feb 2009
    Posts
    227

    Re: Question: What is this?

    I own about half a dozen lenses with separations like that - several Rodagons, a Mamiya RB lens and somewhat else.... I actually do not remember which ones exactly, because they all perform just fine. Unlike the classic Canada balsam separation that often makes the lens hazy thus reducing the image contrast considerably, the modern synthetic cement separations with their dichroic mirror appearance just look like a total disaster but actually have almost no effect on the image quality. Years ago, I undertook precise image contrast measurements as well as the sharpness tests with several pairs of identical lenses - the new ones and those with cement separations like shown above - and was really surprised as I just could not detect any image contrast reduction in the separated ones. (As for the sharpness, it just could not (and did not) get worse as the gap between the separated elements is always too tiny to have any influence on the lens aberrations.)

    So my advice is: just use them. And if worried about having the glass that's not the best available, borrow some mint lenses of the same type and compare them to your lenses in practice.

    The only additional trouble with element separations like the above that I experience from time to time is that when the lens is taken from a cold environment to a warm one, moisture condensation appears not only on the outer glass surfaces but inside the separation, too. And it's not possible to wipe it off from there.

  9. #9

    Join Date
    Jun 2015
    Posts
    49

    Re: Question: What is this?

    Thanks, I needed that! Great info. Merry Christmas

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