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Thread: Turner-Reich modifications?

  1. #11

    Join Date
    Nov 2006
    Location
    CA Central Coast
    Posts
    608

    Re: Turner-Reich modifications?

    Did anyone do the math?
    I get, from the reciprocal of the sum of reciprocals of 19.7 and 25, not 12 but 11", and 12" for 21+28
    Well it's not math but arithmetic, and I'm old , so please verify

  2. #12

    Join Date
    Feb 2009
    Posts
    155

    Re: Turner-Reich modifications?

    Quote Originally Posted by Corran View Post
    I wouldn't expect much from the single elements. I had a 12" TR triple (of the 21/28 type), and both the single elements were pretty bad, even stopped way down.
    Thank you. So those aren't on par with ser.VII Protars.... that makes the TR's of little interest to me, and the only possible alternative is perhaps a Wollensak Ia (bought one also but again haven't got it yet).

    In fact, I was very sceptical about any single elements of any convertibles for years (having tried half-Dagors, Convertible Symmars and Sironars, etc., etc.). But the VII Protar was reported in this forum to be way better so I purchased it, and I really liked it. Wollensak Ia was said to be about as good (except in coverage) - I'll verify that with my own eyes soon.... But I am told different things on the T-R, including that it suffered from a lot of sample-to-sample variations. If it did, I guess my question about the version-to-version difference in just pointless.

    And BTW there also is an older 8/4 Wollensak I (aka Royal Anastigmat) on the 'bay now. Any advice if its singe cells are worth trying?

  3. #13

    Join Date
    Feb 2009
    Posts
    155

    Re: Turner-Reich modifications?

    Quote Originally Posted by EdWorkman View Post
    Did anyone do the math? I get, from the reciprocal of the sum of reciprocals of 19.7 and 25, not 12 but 11", and 12" for 21+28. Well it's not math but arithmetic, and I'm old , so please verify
    That formula is only an approximation. One can get different focal length combinations from the same single cells by changing the distance between those cells. What would the image quality be, is another question....

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