Radioactive Lenses (Yashica Lenses?)

AgX · Nov 6, 2017

shutterfinger said:
As stated before the only way to know for sure is to test the lens in question with a geiger counter or test to see if it fogs film. If glass associated with radioactive lens was used one batch of elements may be more radioactive than others or not be radioactive at all. Its not the sands used to make the glass but the contaminates that were in the sand and were not known to be there until after the fact, later production removed the contaminates before making glass from the sand.

The issue with radioactive lenses is not about contaminants in the minerals used which might raise the level above average (I even do not know of such cases), but about deliberate adding of such.

AgX · Nov 6, 2017

Another issue is the limited means and ability of the common Apugger in metering radioactivity .

The autoradiography test hinted at repeatedly above seems a practical means..

OlyMan · Nov 6, 2017

My dad owned cameras with so-called radioactive lenses since long before I was even thought of. Hasn't ever done him any harm and he's in his 80s now. Though I was four before I found out that other kids don't have three nipples and twelve toes.

E. von Hoegh · Nov 7, 2017

Errrm. Has anyone looked into the type of rays, and the intensity thereof?
It's like radium watch dials, made the dial painters die horribly, but the alpha rays wouldn't make their way through the watch to injure the wrist of the wearer of the watch.

Cholentpot · Nov 7, 2017

My Kodak Signet 50 got me pulled over at the US Canada border. The thorium lens set off a detector. At least that's the excuse they gave me for pulling my car out of line.

AgX · Nov 8, 2017

E. von Hoegh said:
Errrm. Has anyone looked into the type of rays, and the intensity thereof?
It's like radium watch dials, made the dial painters die horribly, but the alpha rays wouldn't make their way through the watch to injure the wrist of the wearer of the watch.

There is not only Alpha radiation. The Thorium decay in some steps also emitts Gamma and Beta rays.

I'm not even sure that all amateurs who tested their lenses had meters that could meter Alpha radiation.
To the contrary: the author of a text on that issue, and the most comprehensive tests I know, used a meter which technical data explicitely only states the ability to meter Gamma and Beta radiation.

benjiboy · Nov 8, 2017

I own a Canon FD 35mm f2 Thorium lens and asked my eldest son a few years ago,( who is a nuclear physicist, and safety officer at one of Britains nuclear research facilities), to look into this matter and after checking the radiation emissions of my lens with a Geiger counter and doing some further research told me that it doesn't emit one-tenth of the radiation that is officially allowed to be ingested annually by workers in the nuclear industry and that it's perfectly safe to own and use, as long as you don't sleep with it under your pillow, and if it was so radioactive it would fog the film in the camera., and the reason the Japanese government banned the use of radioactive materials in lens manufacture was a health and safety issue for the workers who ground the lens elements in the manufacturing process breathing in the glass dust, which is highly dangerous, not the final consumers.
.
P.S he also said that the granite worktops we have in our kitchen emit more radiation than my lens.

Saganich · Nov 8, 2017

I have a collapsible Summicron with radioactive front element. Using a calibrated energy dependent ionization chamber the front element measures 0.7 mR/hr and 0.2mR/hr at the rear element when at full extension. The dose to the eye is less then 0.001mR/hr when attached to my Leica MP camera and at full extension. In this case the distance from the front element to the eye, the shielding provided by the camera body, and the minimum amount of time the camera is at the eye reduces the probability of harm from radiation to nearly zero. The dose at the film plane was approximately 0.2 mR/hr indicating that film should not be left in the camera with this lens attached for long periods of time. The spectrum from the front element shows a characteristic gamma peak at 65 keV corresponding to Thorium-232 and 85keV corresponding to the decay product Thorium-228 (half-life ~2 years). The dangerous issue are the alpha's that are trapped in the glass and cannot escape unless one would ground the glass into finer particulates that could be inhaled. The inhalation of such fine particulates with high energy alpha would cause lung damage..similar to polonium in cigarettes. It's the alpha bombardment that causes the discoloration within the glass.

Wallendo · Nov 8, 2017

A student breaking a lens will not "spill" radiation, as the radioactive material remains within the glass fragments. Injury from the glass fragments themselves is of greater concern.

benjiboy · Nov 8, 2017

As I wrote in post 32 the Japanese safety executive banned all manufacturers the use of the radioactive element in lens glass manufacture because of the danger to workers ingesting the dust from the glass when grinding the lens elements, which is highly dangerous.

MattKing · Nov 8, 2017

I can't resist...
But does the lens give your photos that magical glow.....?

Svenedin · Nov 8, 2017

No it just makes you think there is a magical glow to your photographs after your brain is irradiated but only after you have had your lenses on your pillow night after night for years.

Theo Sulphate · Nov 8, 2017

Word on the street is that a Canon 50/1.0 EF L USM can cook a turkey.

Sirius Glass · Nov 8, 2017

Theo Sulphate said:
Word on the street is that a Canon 50/1.0 EF L USM can cook a turkey.

Do you mean that a Canon 50/1.0 EF L USM is a turkey?

Christiaan Phleger · Nov 9, 2017

No just the first generation ultrasonic motors are the turkey.

Radioactive Lenses (Yashica Lenses?)

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