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Thread: Docter Optic Tessar, Apo-Germinar MTF curves

  1. #1
    the Docter is in Arne Croell's Avatar
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    Docter Optic Tessar, Apo-Germinar MTF curves

    Just a short note that I expanded my article on the Docter Optic lenses (http://www.arnecroell.com/docter.pdf) with an appendix containing scans of the original Docter leaflets, by kind permission of the successor company, Docter Optics. The appendix starts at p. 19 and is 45 pages. The leaflets are (obviously) in German, but I have listed some explanations on p. 19, and MTF curves are pretty universal. It contains the MTF curves plus other data for all their Tessars, Apo-Germinars, and Apo-Germinar W lenses (not for the Germinar W, I have never seen any MTF curves for those). The appendix doubled the file size of the article to 12MB, so be patient with the download.
    In the last few months I also reworked my other lens articles on that site (http://www.arnecroell.com/publications), mostly integrating tables and images into the text of the older articles, and redoing/adding "lens porn" images ;-)

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    While we are at it: I have one Tessar, bought mint in a cardboard box of obvious GDR provenience, labelled "MEYER-OPTIK 1:4.5 f=210mm Made in Germany 0021". By the very pale coating that resembles that on the Docter Tessars presumably multicoated. Do you have any idea where in the timescale that one belongs?

  3. #3
    the Docter is in Arne Croell's Avatar
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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Sevo, 1990-1991. It was made by Zeiss for Meyer after the wall came down and before Meyer was closed down by the Treuhand, to be sold with their "Globica" studio camera. Check the Meyer section on pp.1-7 of this article: http://www.arnecroell.com/eastern-bloc-new.pdf. Fig. 5 on p.6 shows a comparison picture of those "Meyer" lenses and their CZJ counterparts.

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Arne:

    Thank you very much for this valuable piece of info. By the way, I was told there is a shop in Spain that stocks some brand new Docter lenses, specially one apo Germinar 750/14,5. I┤ll visit them.

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Many thanks, Arne, for this invaluable info.

    I'll pass it immediately to our French MF/LF forum http://www.galerie-photo.info !

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Quote Originally Posted by Arne Croell View Post
    Arne, I really appreciate your work. Though I'm pretty familiar with a great number of lenses mentioned in your publication, there still are quite a few things completely new to me, too.

    Would you mind a little correction (mostly on the local terminology) though?


    RF-3, RF-4 and RF-5 process lenses are not 4/4; they are 6/4 symmetrical Apo-Planar type ones. (Not bad glass at all but alas they've got the worst of the Soviet coating versions - the 2-layer chemical one. The single coating on the I-11 and O-2 and O-6 process lenses is much better.)

    Quote Originally Posted by Arne Croell View Post
    A capital "M" marked a process lens, and a capital "S" ("C" in Cyrillic) appears to indicate a sunk mount (so "MC" on a Russian lens does not mean multicoating!)
    • "MC" on a Russian lens does mean multicoating, and nothing else but multicoating. (I can't forget my surprise when I read in a Minolta book that their "MC" meant "Meter-Coupling"!) But: the Soviet terminology assumed 3 layers were enough to call it MULTIcoating, so do not expect the Soviet MC be as good as an SMC or T* - though the Soviet MC is usually better then the Soviet single or 2-layer coating.

    Also, all the Soviet era MC lenses were marked as such (and sold for up to 1.5 times more then the non-MC ones). Any lens made in USSR and not marked "MC", has less then 3 layers of coating applied.

    The "MC" was put in front of the lens name, such as "MC Jupiter-9".

    • The "M" in the end on the lens name ("I-11M", "Jupiter-21M", etc.) is for "Modified". The modifications were different but they always were barrel modifications, the optics being the same.

    • There was no one-letter mark to indicate a process lens ("reproductsionnyi ob'yektiv" in Russian - no "m" in any of the two words, BTW).

    • The Russian for "sunk mount" is "uglublyonnaya oprava" - which contains no "s", and it was never marked as "S" ("C"). In fact, no special mark was used for a sunk mount (though any new mount could be marked with an "M").


    • Also, I've recently posted a bit of info on Russian aerial lenses here: http://www.largeformatphotography.in...it-exist/page5
    Last edited by ridax; 8-Jun-2013 at 07:56. Reason: typos

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Cheers for this Arne. I don't understand mtf graphs much but I read your Docter article and the enlargements from the Germinar shown alongside other process lenses like the G-Claron told me that the Germinars are quite special in their fine detail and resolution. It's a shame the GDR LF lenses are so hard to find, about the only one I ever see for sale is the 4.5/210 Tessar.

    I've got a chance to buy an RF-5, a 450mm lens would be useful, bu I'm umming and ahhing about it, given the nature of Soviet QC. However, being made by LOMO it might be better in that regard, it's a 1990s model so i do worry about the QC in that late period.

  8. #8
    the Docter is in Arne Croell's Avatar
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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Quote Originally Posted by ridax View Post
    Arne, I really appreciate your work. Though I'm pretty familiar with a great number of lenses mentioned in your publication, there still are quite a few things completely new to me, too.

    Would you mind a little correction (mostly on the local terminology) though?


    RF-3, RF-4 and RF-5 process lenses are not 4/4; they are 6/4 symmetrical Apo-Planar type ones. (Not bad glass at all but alas they've got the worst of the Soviet coating versions - the 2-layer chemical one. The single coating on the I-11 and O-2 and O-6 process lenses is much better.)



    • "MC" on a Russian lens does mean multicoating, and nothing else but multicoating. (I can't forget my surprise when I read in a Minolta book that their "MC" meant "Meter-Coupling"!) But: the Soviet terminology assumed 3 layers were enough to call it MULTIcoating, so do not expect the Soviet MC be as good as an SMC or T* - though the Soviet MC is usually better then the Soviet single or 2-layer coating.

    Also, all the Soviet era MC lenses were marked as such (and sold for up to 1.5 times more then the non-MC ones). Any lens made in USSR and not marked "MC", has less then 3 layers of coating applied.

    The "MC" was put in front of the lens name, such as "MC Jupiter-9".

    • The "M" in the end on the lens name ("I-11M", "Jupiter-21M", etc.) is for "Modified". The modifications were different but they always were barrel modifications, the optics being the same.

    • There was no one-letter mark to indicate a process lens ("reproductsionnyi ob'yektiv" in Russian - no "m" in any of the two words, BTW).

    • The Russian for "sunk mount" is "uglublyonnaya oprava" - which contains no "s", and it was never marked as "S" ("C"). In fact, no special mark was used for a sunk mount (though any new mount could be marked with an "M").


    • Also, I've recently posted a bit of info on Russian aerial lenses here: http://www.largeformatphotography.in...it-exist/page5
    Dear ridax,

    thanks for your remarks and corrections, I'll correct the terminology and errors in the article. As for the RF-3,4,5 lenses, they are pretty easy to take apart even without tools, so I just checked the inner cell of my RF-4 again, and you are right, there is a very, very faint reflection from a cemented interface in the inner groups, which makes it a Planar type as you said. I overlooked that before. What about the RF-1? Unfortunately it is more difficult to take apart, and I couldn't see the reflection from a cemented interface, but it was difficult with the reflecting aperture blades in the background using light source reflections on the whole lens half. Is that a Planar type, too?
    Maybe you also know the answer to a recent question on another lens we discussed here, its about the unknown logo of a company, see: http://www.largeformatphotography.in...ufacturer-logo
    Thanks,

    Arne

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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Hi Arne

    Have you shot your RF-4? Just wondered how they were compared to other process lenses asI have the chance to buy an RF-5.

    Ian

  10. #10
    the Docter is in Arne Croell's Avatar
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    Re: Docter Optic Tessar, Apo-Germinar MTF curves

    Quote Originally Posted by Arne Croell View Post
    Dear ridax,
    As for the RF-3,4,5 lenses, they are pretty easy to take apart even without tools, so I just checked the inner cell of my RF-4 again, and you are right, there is a very, very faint reflection from a cemented interface in the inner groups, which makes it a Planar type as you said. I overlooked that before. What about the RF-1? Unfortunately it is more difficult to take apart, and I couldn't see the reflection from a cemented interface, but it was difficult with the reflecting aperture blades in the background using light source reflections on the whole lens half. Is that a Planar type, too?
    Ok, I can answer that myself, since I did manage to get at the inner group cell, although for this one tools are needed, and one has to go in by removing the retaining ring on the outside, then the two groups fall out. The RF-1 is a Planar type, too.

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