Did the Jupiter 12 ever have a thorium-containing element?

Discussion in 'Classic Manual Cameras' started by mr.wind-upbird, Nov 29, 2005.

  1. I recently purchased a Jupiter 12 lens in Leica screwmount, serial number 5904613 (apparently made in 1959), and have noticed that it appears to be somewhat yellowed. You can see the difference in color rendition in these examples. With the Summicron shot as a reference, the one taken through the Jupiter 12 is noticeably yellower. Did these lenses have radioactive elements in the late fifties?
    00EM9s-26740084.jpg
     
  2. And here's the Jupiter shot.
    00EM9t-26740184.jpg
     
  3. Oh, and the Summicron was at f/2.
     
  4. Probably NO lens of the late 50s had thorium glass, and probably very few had thorium before.

    In the 'Annals of optics and precision engineering' (Jahrbuch für Optik und Feinmechanik) it was mentioned in the early 60s (don't remember the date) that thorium was soon replaced by lanthanium. The east german 'ABC der Optik' (encyclopedia of optics, a very comprehensive manual) even does not mention thorium as ingredient for optical glass in 1961.

    I don't know what causes the yellowing but I am pretty sure that it is NOT thorium.
     
  5. Lanthanum would be correct, other lensmakers have used it Leica Voigtlander and Pentax among them . Best known is the Apo Lanthar mine did color yellow and I sold it. Someone here pointed out the discoloration will come back to neutral if the lens is exposed to ultraviolet.
     
  6. This has been discussed many time here before. Prolonged exposure to direct sunlight will clear the yellowing. Takes a day ot two in summer sunshine. May take a good while longer here in Europe in winter.
     
  7. Winfried, your sources may have reported only on German lens and glass makers. And I think they missed Schneider Repro Clarons; I recently sold a radioactive 1963-made 55/8 Repro Claron. I have three Taylor, Taylor, Hobson tessar type process lenses, two from the late '50s and one from the mid-'60s that have thoriated glass elements. And IIRC Pentax made a number of lenses with elements made from thoriated glass into the '70s.

    Noboru, find a Geiger counter or the equivalent and see what it says about your Jupiter 12.
     
  8. The Jupiter 12 is the Russian clone of Carl Zeiss Jena Biogon 35mm F2.8 and was firstly assembled from parts delivered by Russians from German plant after the end of WWII. Then after original parts had been fully consumed they started use the same technology and optical glass for the Jup 12.

    As you probably know, Dr. Ludvig Bertole computed the Biogon 35mm in 30-es in times when the glass containing the rare earth elements was not in use. So, Jupiter 12 does not contain such a glass. The lanthanum glass was produced in 50-es and used for recomputing the Leitz Elmar 50mm F2.8, CZ Tessar 50mm 2.8, Tessar 75mm 3.5 and others lenses to be improved in their speed and resolving power.

    The yellowish rendition of the J12 appears to be due to specific coating of the lens elements.
     
  9. I think Victor is correct. There are many cheap lenses with yellow coatings. Yellow filters off UV and that was the purpose of such coatings.
     
  10. I just checked my '86 vintage J-12. Yep, there's a slight yellow tinge to it, very slight, probably less than a skylight filter (I don't have a skylight filter handy to check against).

    I thought though, that lens coatings were not supposed to affect the color rendition, is this an example of a poor choice of coating?
     
  11. Definitely, the color rendition is different on both pictures but, aside from the color differences and comparing the two, IMO, there are no discrepancies concerning bokeh, in as much as a cheap lens versus an expensive "king of bokeh"!

    My Nikkor 50/1.4 bought in 1968 has an amber coating and it was not an "el cheapo". The same goes for my Nikkor 58/1.4 as well as my Nikkor 105/2.5.

    James, is right as the coating on a lens does not affect the picture color rendition ...the glass formula does.

    Cheers, Tito.
     
  12. Almost all of the vintage coated lenses of late 30s to 60s tend to be incorrect in their colour rendition since they were computed for B&W photography.

    Look at the front surface of any vintage CZJ lenses like the Biotar 58mm F2.0, the Biogon 35mm, Tessar 75mm of S. Iconta, the Sonnar 85mm, the Foightlender Scopar 105mm (notice, please: not the Color-Scopar) you can see the blue colour of coating film of the lens surface. It means that mostly the blue light is reflected with that coating film, whereas the rest light beams (yellow, red, etc) are passed through the lens. This is why such a lens produces the yellowish colour of image.

    Later in 60s every surface of every element of the lens used to be coated with its own colour film, so the common light flow passed through the lens gets to be balanced in its spectrum.
    The MC-coated lenses are the best for the colour photography.
     
  13. Not necessarily true that one needs multi coatings on lenses for colour photography. The older APO Nikkors I have do not have any coating at all. They are very well corrected for the entire visible spectrum.
     
  14. Victor Randin wrote "Almost all of the vintage coated lenses of late 30s to 60s tend to be incorrect in their colour rendition since they were computed for B&W photography."

    Victor, I think you are nearly completely mistaken. You've swallowed a lot of propaganda from, in particular, Voigtlaender. Note that there are very few pre-WWII coated lenses made for civilians.

    You clearly don't understand that without heavy filtration, taking black/white pictures with panchromatic film uses the entire visible spectrum. If a lens suffers from chromatic aberration, b/w pictures taken with it without heavy filtration -- to make transmitted light more-or-less monochromatic -- will be "soft".

    Have you never heard of Kodachrome? Kodak Ektars, coated and not, are very highly corrected for color.
     
  15. Dan Fromm wrote: <You clearly don't understand that without heavy filtration, taking black/white pictures with panchromatic film uses the entire visible spectrum. If a lens suffers from chromatic...> and so on.

    Dan: You are speaking about optical aberrations of the lens, which are the problems to be solved by use of modern lens construction and glass. I would like you and us to consider the fully corrected lens only as the J-12 to be, but not those of primitive examples of the lens of Galileo times. Do not make me wrong by confusing the lens formula with the quality of lens coating. For regular colour rendition the lens should give us the same spectrum it accepts, in ideal case the light came through the lens should be neutral white. I would like also to clear what I have said in previous messages.
    1. Any modern uncoated anastigmatic lens gives the regular colour rendition though with lesser colour contrast due to dispersion and mixing of the main colours of the subject in the optical system of the lens. For example, the portrait shot on the green background tends to be greened, on the brick wall to be reddish. The shadows of the trees being on the picture with the sea and the blue sky are looking to be bluish.

    2. Very bad-coated lenses (very eary Leitz Summitar, Summarit, vintage Russian lenses, etc) make the light a bit coloured and affect the colour of the image.

    So, as for me it is better to use a nice clean and clear uncoated lens than that having bad coating.

    For me the J-12 coating is acceptable and allows making very good pictures. I have three of them and the CZJ Biogon in Leica and Contax mounts, and each of them gives its own colour nuance due to the difference in their coating.

    BTW, I have about 50 lenses for large, medium and 35mm formats, many of them are uncoated, i.e the. two Ektars, four Dagors, three Angulons, two Tessars, Leitz Thambar....
     
  16. "I have three of them and the CZJ Biogon in Leica and Contax mounts, and each of them gives its own colour nuance due to the difference in their coating."

    Current Summicrons and the new ZI Planar also differ much in their colour cast. Nothing to do with lack of coating or difference in coating. Lens materials used themselves play a huge part.
     

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