Quote Originally Posted by titrisol
"radiactive" lenses containe less radiation than your home smoke detector system
No.
Quote Originally Posted by titrisol
and probably than your watch.
Certainly not - unless your watch was made no later than 1930.

Quote Originally Posted by titrisol
Is just a legend given by the use of rare-earth in the fabrication of glass.
No - the radioactivity is real. Some lenses are more radioactive than others.
Quote Originally Posted by titrisol
Those lenses are probably the best ever made
No - newer lenses with similar but "cleaner" glass are better. QV the Cosina-Voigtländer APO-Lanthar 90mm - blows the competition right away, including the 1970's APO-Lanthar.