radioactive lenses

[Chris101]

Unless you have fluorinated fruit, I wouldn't worry about acid leaching uranium out of glass. Silica is not particularly soluble in most acids. (I wouldn't however, store toothpaste in a uranium glass bowl, but then, who would?)

 

[Wolf Rainer Schmalfu]

Radiation?

Radiation?

Older lens glass elements had some minor radiation, bur only for the people working directly on the griding of the glasses or assembling the lenses. Since an few years, it is at least in Europe prohibited to use such optical with some radiations anymore. For all photographers there is absolutely no danger on this subject.

 

[jm51]

Just curious, do hot lenses tend to get less/more fungus or does it make no difference?

 

[filmtwit]

Only the early version of the 58mm f1.2 rokkor was radio active. So you're also getting a single coated lens. I use mine of a canon 50d and had some really odd colors and flares come from it.

I didn''t know the big Rokkor was a glower.

Good to know. This is the best non Leica lens I own. Maybe not so technically when compared to my Pentax limiteds, and I wish it worked on a modern camera system, but the Rokkor 58/1.2 is a killer lens.

 

[sevo]

Since an few years, it is at least in Europe prohibited to use such optical with some radiations anymore.

Says who? The regulations I have seen so far allow the use of thoriated glass in camera, microscope and telescope lenses, but explicitly forbid their use as ocular lenses and eyeglasses. The im- and export of these lenses across European borders isn't prohibited either. However, workplace safety and environmental pollution regulations make it effectively impossible to produce them any more, whether in Europe or elsewhere. Not to speak of the cost of nuclear waste disposal - if you own a broken one, about the only place where you can legally get rid of it without paying a small fortune would be ebay...

 

[ssmc]

Just don't carry those lenses in your underpants if you wanna have kids

No, but seriously folks...

There are far more intensely radioactive minerals, such as pyrochlore, that occur naturally, than you will find in a "hot" lens. Fortunately they are uncommon.

Unfortunately, as others have pointed out, the very word "radiation" has been made into a sort of modern day boogey-man, irrespective of context (as in the gamma-sterilization of food and medical supplies).

Thoriated glass is not "nuclear waste", btw. Thorium 232 (the most common isotope in nature) has a half-life of 1.4 billion years (about the age of the universe) and is virtually inert as a consequence. If manufacturers really needed thoriated glass and were willing to spend the $$$ to separate Th232 from the other isotopes it would be completely safe, as the optical/chemical properties are not dependent on the radioactivity. The main risk to the user from having oculars/eyeglasses with radioactive glass is cataracts.

One other thing - the Am241 used in smoke detectors is an alpha, not neutron, emitter (secondarily, a low-energy gamma emitter) and the little sheet-metal cage around the source is more than adequate to stop any alpha particles. Neutron emitters are exceedingly rare.

 

[kram]

I will be a pendant, for once. ssmc I agree with you. However, a little known fact,Am-241 does produce the odd neutro now and again. I have not got the precise info to hand, but if I recall correctly 1MBq of Am-241 give off 0.3 neutrons! that is to get 1 neutron a second from Am-241 you would need 3.3MBq.
I helped produce metal scrap monitors and insisted they had neutron detectors - mainly to pick up large Am-241 sources.

 

[kram]

Two more things: thoriated lenses are exempt if you are company, and are 'out of scope' if you are Joe Soap.
No fungus on my radioactive nikon 35mm f1.4 lens