Quote Originally Posted by Poisson Du Jour View Post
Old Pentax Takumars often had thorium in them. No news here.
I bought an old Spotmatic a few years ago with a 55 1.8 Super-Takumar. This was before I knew anything about the radioactive glass. It looked lile every piece of glass in it was made from melted-down 81B filters. I could have put a bulb behind it an used it as a safelight. I had never see such a sight. They say you can put it out in the sun and bleach it. That summer I'd carry it out and put it on the deck rail every day, and it did lighten up some, but not entirely. The lens was essentially ruined.