Lens radioactivity

guangong · Aug 15, 2018

Theo Sulphate said:
I have seen people in their cars, stopped in the middle of the road for over five minutes, while texting on their cellphone. I am seeing behaviour today that would be inconceivable 25 years ago.

I won't even go into detail about people getting their information and making decisions based on Twitter, Facebook, Netflix, and other instantaneous "news" sources.

Perhaps we have created a level of technology, in many things, that we cannot handle as a species and it will become our doom.

In New Jersey, certified by insurance companies to share worst driver status with Massachusetts, I have experienced cars stopped dead in the left fast lane of interstate highways while they play with their toys. Not to mention the drivers that site for many minutes at in intersection while they fumble with toys. They are even more annoying than old geezers who poke along at 20 mph for miles in no passing zones.

Sirius Glass · Aug 15, 2018

guangong said:
In New Jersey, certified by insurance companies to share worst driver status with Massachusetts, I have experienced cars stopped dead in the left fast lane of interstate highways while they play with their toys. Not to mention the drivers that site for many minutes at in intersection while they fumble with toys. They are even more annoying than old geezers who poke along at 20 mph for miles in no passing zones.

In both state, when one applies for a drivers license one half of the brain is removed. If one had half the brain removed in the other state, half of the remaining brain is then removed.

Bud Hamblen · Aug 24, 2018

I measured a Kodak Pony 135 model C with a cheap geiger counter and got readings in the range of 0.92 micro-sieverts per hour. Normal background is about 0.12 micro-sievert per hour. If I move the meter even a small distance away from the lens I don't see anything above normal background. It was interesting that Eastman Kodak put special glass in what was their cheapest 35mm at the time. The Kodak produces a warm image. There is a lot of thoriated glass out there. John Walker (https://www.fourmilab.ch/documents/radiation/lens/) has an informative post.

dynachrome · Aug 24, 2018

BMbikerider, I have not seen any 28/2.8 Minolta MC Rokkor lenses with discolored glass. I thnki you meant to say 28/2.5 MC Rokkor. These do not have thorium coated elements. The thorium is part of the formula when the glass was made. I have several of these f/2.5 lenses and have lightened them by exposing them to UV light. I do not say that I have completely cleared them because I don't know if that's possible. I wouldn't use them with color slide film but they work for color negative film because the color is corrected in the printing process. These f/2.5 lenses are sharp and lightening them up makes focusing and using them in low light easier.

Arklatexian · Aug 24, 2018

Sirius Glass said:
This has been covered before in threads. Basically the amount of radioactivity in lenses is not enough to be concerned about even over long periods of time.

Does any of this group worry about the amount of radioactivity absorbed in an airplane crossing the Atlantic or Pacific at high altitudes? I'll bet that is much higher than any radioactive lens puts out. I have made 10 round-trips over the Atlantic and have yet to fog either film nor paper by glowing in the darkroom......Regards!

AgX · Aug 25, 2018

Based on some accidentally taken figures from lens meterings on the net, 10h wearing a camera lens next to oneself would be equal in magnitude to 1h flight in a highflying plane.
But as said above metering ionizing radiation is tricky in laymen's hands.

pentaxuser · Aug 25, 2018

I wonder what the comparable background radiation is compared to the camera lens for residents of such cities as Aberdeen, Scotland where the whole of the main part of the city is granite buildings. I am not sure if granite is still being hewn out of quarries around Aberdeen but for probably over 100 years there were hundreds working in such quarries. Once there were instruments to measure radiation and its effects became known, you'd have thought that the medical research department at Aberdeen University or other research establishments would have embarked on a study on the incidence of radiation related problems in the local population compared to other areas of Scotland and whether the incidence of such problems were even greater in the granite quarry workers.

Certainly I don't recall Aberdeen being sited as a dangerous place to live and work in, nor any news that granite quarry workers were at greater risk from radiation.

pentaxuser

AgX · Aug 25, 2018

Aberdeen has no nuclear power plant. Antwerp has one at its city limits.
There are so many facets on this topic...

benjiboy · Oct 21, 2018

I have a Canon FD 35mm f2 Thorium lens that I've had for more than thirty years, I asked my eldest son ( who has a PhD in nuclear physics and is a safety officer in a leading British nuclear facility) a few years ago because I had seen all these people with Geiger counters going crazy with thoriated lenses on Youtube how safe it was to own it, he told me after he had tested it that it didn't emit one-hundredth of the radiation that workers in the nuclear industry were allowed to safely absorb annually and that as long as I didn't sleep with it under my pillow every night it was O.K. and at my age I shouldn't worry about it, and that the Youtubers only proved the old axiom " a little knowledge is a very dangerous thing" .

pentaxuser · Oct 21, 2018

Sirius Glass said:
This has been covered before in threads. Basically the amount of radioactivity in lenses is not enough to be concerned about even over long periods of time.

Damn. I have taped such a lens to my hands in the hope that at my next visit to Las Vegas I can empty the fruit machines It worked for Mickey Rooney in "The Atomic Kid"

pentaxuser

Lens radioactivity

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