Wear your lead vest when using these lenses

[Mainecoonmaniac]

On some of these lenses, most of the radiation comes from the rear elements. Are these radioactive lens that much sharper?

https://www.youtube.com/user/uyt384

[LarryP]

they tend to be damn nice. I wouldn't worry about radiation from any lens that doesn't fog the film Just sayin'.

[PentaxBronica]

It occurs to me that you can make any measuring device appear to indicate a high reading by simply changing the units it measures in. I can't see what his geiger counter is measuring in, but the racket it makes suggests that he's switched it to be hyper-sensitive for an impressive result. If they were really as dangerous as the sizzling noise suggests then there would be camera collectors dropping dead from radiation poisoning all over the place!

[E. von Hoegh]

Has anyone bothered to find out just what paticles these lenses emit? You may wish to....
And as PentaxBronica said, you can make a meter say anything.
Lastly, it's on utoob ffs. Check out the bigfoot and ufo videos.

[PentaxBronica]

The fact that there's a much lower reading (regardless of sensitivity setting/units) when he puts the sensor against the front of the lens (and around the back until he presses it against the lens) would suggest that they're pretty weak particles. I'd expect the mirror, pressure plate, and back door of an SLR to block them pretty effectively.

Remember, a lot of substances aren't dangerous due to radioactivity. It's because they're a toxic metal like lead. Ingest them and you'll suffer from heavy metal poisoning rather than radiation sickness.

[Gerald C Koch]

The two most common radioactive metals used in making certain optical glasses are thorium and lanthanum. Unless you are going to sleep with one of these lenses under your pillow for months you are not at any risk. The refractive index of such glasses permit designers to make lenses with fewer elements or increased speed and contrast.

[Mainecoonmaniac]

The refractive index of such glasses permit designers to make lenses with fewer elements or increased speed and contrast.

Thanks for the information. Are there other glass additives that do the same without the radiation?

[benjiboy]

One of my son's is a nuclear physicist who works at a World renowned nuclear facility here in the U.K, I have a Canon FD mm f2 Thorium lens and asked him to research if it was safe, he told me the level of radiation it emits is very small and a fraction of that that workers in the nuclear industry are allowed to absorb annually, he also said that it wasn't much more than that emitted by bananas, or Brazil nuts, however he did say he didn't recommend that I sleep with it under my pillow.

[RidingWaves]

Yes there are many glass additives that do the same, or close enough. In the early-mid 1970's the use of Thorium was phased out due to worker health, the dust from the grinding and polishing if inhaled was very bad. Later, the use of lead was cut down or eliminated (as widely touted by Canon).

[BrianShaw]

How would we see through the vest? I'd be more worried about getting that eye cancer that travels immediately to the brain.