radioactive glass LTM Summicrons

Discussion in 'Leica and Rangefinders' started by josef_cadek, Nov 7, 2006.

  1. Hi,
    please is it possible to find out which LTM Summicrons have radioactive/
    rareEARTH/Lantanium/whatever glass?
    As far as I know these lenses should have serial number just over 1.000.000.
    But my question is, does anyone know which serials numbers are the ones and
    from which number/year are glasses "normal"?
  2. I do not know the answer to your question. But levels of radioactivity in glass elements of photographic lenses should not make you worry about your health. If this is your concern.

  3. I'd like to know the answer to this question too, as I would be interested in finding a radioactive Summicron!

    I have a radioactive Canon FD 35mm f2 that was made with Thorium in the glass. It doesn't glow in the dark, or anything like that. It has a faint yellowish cast to the glass that doesn't affect my pictures.
  4. Jim Kuehl had one a few years ago. Absolutely mint++, just yellowish/brown glass. Was in screw mount and never used. That perfect. I returned it.

    Jim may not be in business, but his phone is/was
    515 225 0110 and fax is 515 226 0295. or the reverse. My phone book is ?. He used to like the ititial contact to be by fax. He will call you. Keep in mind he is retired and just working from his home with select customers.

    Try the Des Moines, Iowa phone book if you must.

    The black and white pics were fine. Color would be unuseable.
  5. I had a radioactive Summicron with yellowed glass. It took excellent pictures in black and
    white, but color slides weren't so good. Depending on the light, they were either warm-
    shifted or downright yellow-orange. The glass didn't look that bad when held up to a light,
    but it definitely made a difference on film. I don't know the exact serial numbers, but you
    can tell if a lens is radioactive just by looking.
  6. I thought they had serial numbers BELOW one million. But I don't know how far below.
  7. There was an article in the LHSA publication about 10 years ago that investigated just how radioactive the lenses were. (It was variable.) I believe lanthanum was the element of choice in the early Summicron and most of them were made of lanthanum. However, a minority of the lenses were made with thorium. (Perhaps it was a supply issue with lanthanum.) These radioactive lenses are recognized by their yellowed glass. They were made in the early days of the Summicron and hovered around serial # of 1,000,000. I have an early lens with #920,698 which has clear glass and a couple in the 1.02M range with yellowed glass. With B&W film, using the yellowed lens is like using a yellow filter.
  8. Mine is yellow, don't have the serial number handy here, but it's low. I need to bleach it out in the sun.

    I think it was Lanthanum glass, with some trace Thorium, which has a naturally occuring percentage of radioactive isotopes. Their decay yellows the glass. UV light bleaches it out.

    Just shot a test roll with three lenses, and there's clearly a warm cast to the Summicron shots.
  9. See:

    but note also Marcelo's comment at the end of this thread:
  10. Where do you think that famous Leica "glow" comes from?
  11. I am very sure you have alternatives to the LTM Summicrons. Radiation from old lenses are pretty strong and you should worry about the exposure. If you are the only one contacting that lens, it would be fine. But if you have kids and wife around, I strongly suggest you to get rid of it from your home. I checked radiation level of my previous pentax super takumar 50mm, and I was stunned by the screeching sound from the Geiger counter.
    Your health is more important than slightly higher resolution.
  12. There was also a thread in the Classic Cameras forum about the Voightlander radioactive lenses recently. You might look there.
  13. Can't help with the lens but .... I use a 'radioactive' Takumar 35/2 which is a touch yellow/brown. For slide work I use a Wratten/Hoya 82A (or B+W KR1.5) which corrects the colour balance - for a worse 'discolouration' I'd probably use a Wratten 82B. AC
  14. Two separate assessments of the possible risks posed by radioactive lenses from reasonably authoritative sources:

    It seems that there may be no particularly pressing reason for precipitantly disposing of many 'consumer-grade' thoriated-glass lenses, just using them and storing them sensibly. The situation appears to be different for Aero-Ektars and some other specialist, non-consumer lenses.

    Personally, I find the linked page (Oak Ridge site) on Consumer Products far more scary than the thoriated lens issue:

    Having a fossil dinosaur bone or shark's tooth in the livingroom is even more of a risk!

  15. Oh Blatherschythes!

    There's absolutely no reason to get rid of these lenses.

    First, a good healthy dose of UV will bring a red-brown Thorium or yellow Lanthanum lens back to neutrality. You can do it with sunlight, but this involves taking the lens outside, and that may frighten many Leica shooters. You can do it inside, if you have at least one low FE glass window in your house. (Don't confuse "Low FE" with "low E" glass. Low FE is "low iron" or "decolorized" glass, which passes substantially more UV than ordinary window glass. You use it in windows if you like to keep your pet Iguana healthy, or if your house has a "grow room").

    Second, as Alan's nice references mentioned, there's no danger from this glass. Heck, my wife and I have a spectacular collection of radioactive glass. Granted, except for a single radioactive Tak, it's all uranium glass (commonly called "Vaseline glass"), approximately 200 pieces: vases, bowls, candy dishes, goblets, baskets, plates, pickle dishes, juicers. Sitting a few feet from me is a 30 pound pile of uranium glass cullet (big chunks of broken glass). In direct contact with a large Vaseline glass piece it's possible to receive dosages approaching 10% of background radiation levels ;)

    Last, mixing radioactive waste with glass is one of the best ways of making it relatively safe for storage. I've always pictured a radioactive waste dump in the form of a spooky black glass Stonehenge out in the desert somewhere...
  16. hi,
    thanks for answers. I asked because I want to buy LTM Summicron and I want to avoid buying radioactive one. I use yellow filter for B&W sometimes, but only when I want to. I shoot in colour too. No yellow glass for me :)
    Slightly better optical perfomance of radioactive glass does not make any importance for me. Limitation of my photography is in my hands and eye not in gear I have.
  17. You're welcome.

    Now, once again, there's no reason to avoid these lenses. As I said before, and as many people have mentioned on dpReview over the years...

    "First, a good healthy dose of UV will bring a red-brown Thorium or yellow Lanthanum lens back to neutrality. You can do it with sunlight,"
  18. My yellow one is s/n 1024188.
  19. Here's a shot I took about an hour before sunset on Sunday with my yellowed Summicron. This is a straight scan from E100GX, full dynamic range of the CoolScan IV scanner. Just resized, sharpened, and JPEG'd. It's underexposed because of the sheer light loss through the lens due to the yellowing.
  20. Here's the same shot, about 3 minutes earlier, on my new Canon Serenar 50/3.5 lens. This is what things really looked like color-wise. The sun wasn't setting all that fast! OK, still a little underexposed, but it's a fair comparison. Tricky scene to meter with just the reflected light meter in the Canon 7s.
  21. I missed this thread but mentioned just this subject in the later thread on Summicrons, re using the sun to 'bleach' out lanthanum glass - and it's possible effects on the balsam in the compound elements.

    There is a slight difference in the bezel around the front element - single on the early ones and double on the later; I think it corresponds with the different types.

    Spacing out - just got to get to bed.
  22. I am sorry I don't have ready access to the LHSA article on these lenses but it pointed out that possible radioactivity exposure was less than the normal day to day exposure to radon gas. If any one is concerned about possible health issues a reading of the article would dispell any such worries. The sn# range of the lenses with Thorium glass is listed in the article.
  23. Interesting link, but I worry about the guy that considers depleted uranium rounds as "consumer products"...
  24. "... I worry about the guy that considers depleted uranium rounds as "consumer products"..."

    I suppose it depends on where you live: there have been reported instances of attempted (and fatal) recycling of such materials in a few 'interesting' countries ...

    And yes radon (Dan) is a far, far higher (and often crucially underestimated) radiation risk in enclosed spaces and in some, but not all, places - though it can be managed. AC
  25. I suppose this radioactive lens issue will continue to raise the hackles of those who worry about such things despite the numerous postings assuring the readership that such concerns are groundless. Aside from the filter issues involved it would be hoped that it would be put to rest. The filter issue also seems to be corrected with a bit of UV exposure. The lens in question is capable of producing excellent images if the user understands the limitations involved and compensation therefor.

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