The Aldis Projec

Radioactivity
Many rumors circulate on the internet about radioactivity of the Kodak Aero Ektar.
Lanthanum, Thorium, Gamma rays...What's to believe: I've found the extensive report of Michael S. Briggs highly reassuring. I wrote also a veteran of the Korean war about this matter, see his answer below.

Exerpt from Michael S. Briggs report: See the complete article on our link site about RadioActivity>
A further indication that Aero-Ektars are reasonably safe (nothing is perfectly safe) is that their possession by ordinary persons, i.e., persons without a radiation license, is legal in the United States. Title 10, Chapter I, Part 40, Section 13 of the Code of Federal Regulations says in part:
Any person is exempt from the regulations in this part and from the requirements for a license set forth in section 62 of the Act to the extent that such person receives, possesses, uses, transfers or delivers source material in ......
(7) Thorium contained in finished optical lenses, provided that each lens does not contain more than 30 percent by weight of thorium; and that the exemption contained in this subparagraph shall not be deemed to authorize either:
(i) The shaping, grinding or polishing of such lens or manufacturing processes other than the assembly of such lens into optical systems and devices without any alteration of the lens; or
(ii) The receipt, possession, use, transfer, or [sic: the original is missing a word] of thorium contained in contact lenses, or in spectacles, or in eyepieces in binoculars or other optical instruments.
Two elements of the f2.5 Aero-Ektars are made of glass with 11% and 13% Thorium by weight, so this regulation clearly allows possession of Aero-Ektars.
The most basic principle of radiation safety is that radiation exposure should be lowered to the minimum practical level. Regardless of safety calculations, the level of radiation exposure should be further reduced if there is a practical means to do so. This means keeping people far away (many yards/meters) from Aero-Ektars except when one is being used or examined.
Of course, in their original war time use, the danger of the radiation from Aero-Ektars was utterly trivial compared to the more obvious risks that America's soldiers, sailors and aviators took in order to win the war. The substitution of night-time reconnaissance flights for daytime flights made possible by the fast aperture of the f2.5 Aero-Ektars undoubtedly saved American lives.

The rear elements of the Aero-Ektar lenses are famous for having thorium glass that is a mild gamma radiation emitter. This lens element does, indeed, emit gamma radiation, approximately 3 mR/hr. according to my Geiger counter. I looked into what exactly this means to the timid photographer. My brief web research indicates that if you put this lens in your (big) pocket for 8 hours a day, 5 days a week, after six months you would have been exposed to the 5000 mR maximum permissable annual occupational exposure. So, don't grind it up and eat it, use it for a pillow, make it part of your uniform, or put your body in contact with this device on a regular basis.
Beyond a couple feet away, the detected level of radiation disappears into the background.

Report from a user:
in a message dated 10/23/2005 4:57:19 AM Hawaiian Standard Time, jd.esq@tiscali.nl writes:
Dear Dan,
Could you shed some light on the Radioactivity of the Aero Ektar?
I'm doing a site about the Speed Graphic and Aero Ektar.
You have worked with this camera and Lens during the Korean war...What were the rumors...
Please help me out.
Would be glad to publish your comments on my site.

Hi John.
I think the most significant thing is I'm not aware of any information being given to us about the radioactivity. From about April of 1953 to May of '54 I used a K-24 with an Aero Ektar in my work as the Photo Officer for the 3rd Infantry Division and never was told the lens was radioactive. I have an old ad about the lens, published during WWII which praised the lens for its improved glass or design but nothing about radioactivity. The army manual for the K-24 does not mention radioactivity either. I also have suffered no ill effects from any radioactivity, and even though I am a disabled vet and a frequent visitor to the VA clinic in Honolulu, I have never heard of any claim being filed for injuries due to the lens' radioactivity. I only learned about the radioactivity after I started to get back into using one of the cameras, about 3 years ago. When I asked what precautions I should take, the seller of the camera said. "I guess it wouldn't be a good idea to store it under your bed." - And I haven't done that.
Regards, Dan

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