Radioacive element in my Canon FD 35 f2 lens

Discussion in 'Camera Building, Repairs & Modification' started by Uncle Bill, Dec 6, 2010.

  1. Uncle Bill

    Uncle Bill Subscriber

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    I bought my brother's Canon F-1n yesterday along with a couple of lenses, one of them being a '70s vintage 35 f2 which I guess went head to head with the legendary Nikkor O 35 f2 lens.

    Small challenge, one of the elements yellowed, did Canon use any rare earth glass like Pentax did with their 50 f1.4 and can the same UV exposure trick get rid of the yellow? I shoot black and white about 80% of the time but I would prefer a more colour neutral glass.
     
  2. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I have had a Leitz Summitar 5cm and when you look from the outside , it had a brown tint. But it took my lifes most neutral , highest quality pictures. So deciding from outside is not a good idea.
    Get your lens , get your 35 mm film and put your lenses front element on your film strip for few minutes , if there is no burn at your film , there is no radioactive glass.
    Buy a piece of aluminum foil , wrap the back element , and put your front element directed to the sun , if you can find the bright sun at this winter. After 48 hours , if there is radioactive yellow tint , it would be turned to neutral. Summitar have a proven high ratio thorium inside and back element made by lead crystals to prevent burn.

    Good luck , if it is radioactive , it is rare and excellent.

    Umut
     
  3. hpulley

    hpulley Member

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    The original Canon FD 35mm f/2.0 SSC with a concave front element indeed has a thorium element. Most people put it in the sun for a while to bleach it out. I leave mine yellow since I like the effect in B&W as a subtle yellow filter, often enhanced with a #8 filter.

    Absolutely excellent optics! Sharp, sharp sharp! I can blow up pictures made with that lens and the detail is incredible.
     
  4. hpulley

    hpulley Member

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    Oh and here is a comparison of the warmth, can't remember what film this was, E200 or Kodak Gold probably with 35mm f/2 thorium and a normal 28mm f/2:

    [​IMG]
    TRAIN35 by Harry Pulley, on Flickr

    [​IMG]
    TRAIN28 by Harry Pulley, on Flickr
     
  5. benjiboy

    benjiboy Subscriber

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    I have one of these lenses and it's a stunning performer, it was an " L " lens before Canon ever thought of the term, it seems to defy the laws of physics because at all apertures its as sharp at the edges as it is in the middle, this is a legendary lens too.
    They did use rare earth glass Uncle Bill like the Pentax 50mm f1.4 until the Japanese Government prevented optical companys using this glass because of health and safety issues of the workers grinding it.
    I have done a lot of research to find out if there is any danger from owning a Thorium lens, and so has one of my sons who is a physicist on my behalf, and as far as we can tell there's extremely little, only a tiny fraction of the radiation level that is permissible for workers in the nuclear industry.
     
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  6. hpulley

    hpulley Member

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  7. benjiboy

    benjiboy Subscriber

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    My example of this lens Harry is an older chrome nosed version that that was made in November 1971 that isn't marked S.S.C. so it isn't multi- coated, I had mine CLA'd a few months ago because the lens cost me very little and I thought the expense on such a good optic was justified, I even managed to find the original BW 55A hood, it now looks and works like a new one and is my best lens and probably my most used one.
     
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  8. hpulley

    hpulley Member

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    Yes, mine is the II version though Canon didn't mark version on the lens back then. As you say, the original version had a chrome nose.

    I've never had a lens CLA'd though my 28mm f/2's aperture doesn't stop down reliably so I may need to look into it. Just tough when the lenses are so cheap on the used market these days, the labor costs of repair and maintenance seem quite high by comparison.
     
  9. benjiboy

    benjiboy Subscriber

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    The CLA probably cost about £75 probably less that than I could have bought a second hand one for, and I now know that it's reliable and in first class condition, I generally prefer having the equipment I have maintained if possible.
     
  10. Uncle Bill

    Uncle Bill Subscriber

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    I'm going to try out this lens on Friday with my F-1n with some Legacy Pro 400 and see what I get. The lens I have is the early chrome nose FD version.
     
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  11. hpulley

    hpulley Member

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    Let me know if you're going anywhere interesting. We should organize some west-of-Toronto photo walks/meets at some point. Doesn't have to be purely Canon FD based but that would be fun ;-)
     
  12. waynecrider

    waynecrider Member

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    There's probably a few around including myself that would like to have that lens as is.
     
  13. benjiboy

    benjiboy Subscriber

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    I'd be very interested to find out what you think of it too Uncle Bill, I hope you will post something about it when you get some results.
     
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  15. Andrew K

    Andrew K Subscriber

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    as long as the lens doesn't need parts then cleaning one of these lenses is easy...I normally charge around $60-70 AUS to do one...

    The old SSC lenses are quite sharp - although I wouldn't call them L lenses. Canon did have "Flourite" lenses - these had a green band around the hood (if there was a built in hood) - and were marked flourite on th ename ring. Flourite lenses ar enot common - there was a 24mm which I've never seen, a 55/1.2 which they made around 350 off, plus the 300/2.8 flourite. These are all old FD mount.

    There was also a 300mm (F5.6 I think) plus another longer lens which was also a Floutire made in FL mount...

    The OFD 35/2 was a nice lens - but the NFD 35/2 was sharper - at least it was when I tested them side by side...

    But not by much :smile:

    Have fun
     
  16. hpulley

    hpulley Member

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    The 24mm and 55mm were not flourite lenses with a green ring, there were aspherical versions with a red ring, the original reason for red and green rings. The EF mount kind of perverted things where L means it has aspherical or flourite or ED glass while green means the unpopular diffractive optics lenses; I wouldn't be surprised to see green rings repurposed by Canon soon as DO has been a flop, with odd bokeh reminiscent of mirror lenses and high expense.

    Interesting that the new FD 35/2 was sharper. I've never touched one but they're cheap enough to try on a lark these days. Probably some sample variation as well.
     
  17. benjiboy

    benjiboy Subscriber

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    I've tested the Thorium lens against the new type FD f2 and find the reverse but the difference to be too small to be significant for practical purposes, I've also tested the FDn 35mm f2.8 which is also a very fine performer.
     
  18. AgX

    AgX Member

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    There were 3 FD lenses of the type 35/2.5:


    no marking (possibly with chromed front bayonet), concave front lens, 1971

    SSC marked, black front bayonet, concave front lens, 1973

    SSC marked, black front bayonet, re-designed optics, convex front lens, 1976

    New FD-bayonet, black front bayonet, re-designed optics, convex front lens, 1979



    So, I guess you all are talking about the first two ones concerning that radioactive issue.
     
  19. benjiboy

    benjiboy Subscriber

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    Yes that's right, except these lenses were f2 not 2.5
     
  20. Andrew K

    Andrew K Subscriber

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  21. hpulley

    hpulley Member

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    They are still expensive! Surprisingly for all the film discontinuations, even body prices are sky high! I'd like to pick up an F1 but they are still going for hundreds of dollars. The lens price bounce I thought I understood due to the 3/4 digital cameras having lens adapters for everything under the sun but it seems even used on FD bodies the following is going up. The old aspherical lenses and flourite still go for lots of cash, even broken ones! Drab olive F1, forget about it!

    I wanted to get a Pellix with the 38mm f/2.8 pancake but again that seems to go for $400. Just crazy prices.

    Canon only seems to support lenses for about 5 years after they're superceded. It is much worse with EF, once the supply of AF motors and now IS motors is gone, the lenses are bricks as some don't have a manual focus backup and some of the IS controllers when they die actually make the image bounce around making the lens completely useless if they no longer honor the off switch either. But you can buy the new model of course... I still like Canon but they do know how to make a buck it seems, good for them I guess!
     
  22. benjiboy

    benjiboy Subscriber

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    I think the word is getting round what exceptional optics these Thorium rare earth glass element lenses are, and consequently for lenses that are nearly forty years old even though the FD mount has been long orphaned by Canon seem to be increasing in price, which to my mind goes to prove that the latest all singing all dancing lenses aren't necessary the best because they've known how to make great lenses for a long time.
     
  23. hpulley

    hpulley Member

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    The current Canon EF 50mm f/1.4 optics are EXACTLY the same as the 1967 Canon 50mm FL f/1.4 II, no change in FD mount and no change in EF mount. 42 years and counting, good optics stand the test of time. Computerized designs have helped to improve zoom lenses tremendously but for good prime lenses I think the designers in the last century knew what they were doing.
     
  24. benjiboy

    benjiboy Subscriber

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    The difference is that with modern computers physicists can with Computer Aided Design can do what used to take years of painstaking calculations in an afternoon.
     
  25. hpulley

    hpulley Member

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    True though it seems like new zoom lenses and really light, astronomically expensive telephoto lenses are all that come out of those drawings now.
     
  26. AgX

    AgX Member

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    With introduction of the FD true-bayonet lenses a 50mm/1.4 with new optics was released in 1979.