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considering purchasing a 55mm f1.8 takumar. Are these radioactive like the 50mm 1.4?

Discussion in 'Adapted Lenses' started by colbycheese, Jul 11, 2015.

  1. colbycheese

    colbycheese Mu-43 Veteran

    378
    May 1, 2012
    Way up there.
    I was considering buying a 55mm 1.8 takumar but i am pretty concered about the radiation and the health affects. I know that the 50mm 1.4 version is radioactive but i am still unsure of the 55mm 1.8. Is there a way i can determine if this lens has thorium in it like the 50mm. I have read extensively about the radiation of these lenses and i can't come up with a concrete answer whether it is safe or not. I know there is other lens choices out there, but i i don't think my anxiety of radiation should put me off the takumar lenses.
     
  2. coffeecat

    coffeecat Mu-43 Top Veteran

    711
    Aug 4, 2012
    SW England
    Rob
    I've got one of these (tak 55/1.8), I've had it over 30 years. I only recently discovered the whole radioactive lens thing. Exactly like you state in your post, I did loads of extensive internet research and came up with no conclusive evidence one way or t'other. However, if it is radioactive the emissions are not able to get through much (certainly not a camera) so unless you hold it up to your eye or close to your body for long periods it seems not to be an issue. I stopped worrying about mine. It only has a small amount of yellowing visible by looking through it and nothing at all that shows up in photos. My guess it it's probably not radioactive but I don't know. I have a friend with a geiger counter but I never remember to take it when I visit him!

    BTW, it's a really nice lens, although my O45 has made it somewhat underused of late.

    Rob
     
  3. colbycheese

    colbycheese Mu-43 Veteran

    378
    May 1, 2012
    Way up there.
    ok well i still kinda want to grab one because i just love the focus ring and aperture ring of the takumar lenses. I also am looking for something lighter to use in place of my helios 44m. your reply kinda reassures me but i still have my worries. Do takumars with less yellowing have anything to do with the amount of the radioactive material in them?
     
  4. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Most Tak lenses look a little yellow when looking AT the glass.

    The radioactive ones may look yellow when looking THROUGH them... If so, they can be de-yellowed by leaving them on a windowsill for a month or two.

    None of the radioactive Taks are dangerous.

    Barry
     
    Last edited: Jul 11, 2015
  5. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    And there's two main versions of the 50mm f1.4; only the older one is radioactive.

    PentaxForums has a lens database with more info.

    Barry
     
  6. colbycheese

    colbycheese Mu-43 Veteran

    378
    May 1, 2012
    Way up there.
    would you happen to know if the 28mm 3.5 super takumar is radioactive? This is the other lens i was considering getting. I found contradictory info on this lens as well as the 55.
     
  7. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    I don't believe so... No mention of it at
    www.pentaxforums.com/lensreviews/S-M-C-Super-Takumar-28mm-F3.5.html

    Almost certainly, the SMC version won't be.

    Barry
     
  8. Replytoken

    Replytoken Mu-43 Hall of Famer

    May 7, 2012
    Puget Sound
    Ken
    While they may not be dangerous, I did get stopped at a security check at the White House back in the early 1980's while carrying my Spotmatic and 50/1.4. And I can only image what would happen today at places like airports, ferry terminals, etc. where they still monitor for radioactive substances if the lenses are capable of setting off any monitors. :eek:

    --Ken
     
    • Informative Informative x 1
  9. colbycheese

    colbycheese Mu-43 Veteran

    378
    May 1, 2012
    Way up there.
  10. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    PentaxForums says the 55 has a radioactive element "from 1965"... I'm not sure if that includes ALL later versions.

    I do know the SMC 50mm 1.4 isn't radioactive.

    Again, there isn't a good reason not to get one of the radioactive ones.

    Barry
     
  11. bredman

    bredman Mu-43 Veteran

    458
    May 30, 2013
    Sherwood Forest
    Pete
    • Agree Agree x 1