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is my sekor 55mm f1.8 SX m42 lens radioactive


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guys

i bought a mamiya DSX 1000 slr recently and its due to arrive in the next few days

it has the mamiya sekor 55mm f1.s x lens on it.

Is it a radioactive lens

gdf2009 on a youtube link from camerpedia shows it gives a reading of 6.03uSv/h ,

compared to 42.7 uSv/h from an Ashi SMC Takumar 55mm f1.8 for comparison.

But an administrator called vintageslrs on The Camera Colector Website tested states the sekor has normal levels.

What do u think , is 6.03 uSv/h anything to worry about if it is indeed radioactive.

regards Andrew

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There is nothing to worry about in any case - radioactive or not. You get more gamma rays from just living in the earth's atmosphere, and depending on where you live the rock substrate beneath you may be dosing you up as well. Uninformed people fear what they don't understand and take it to extremes. The amount of radioactive emissions from lenses is virtually insignificant, as Rick suggests above. Get over it!
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And then there's cellphones...

 

- Cellphones don't emit ionising radiation, but if you're worried a tinfoil hat can turn a few heads in admiration.

 

"The amount of radioactive emissions from lenses is virtually insignificant,.."

 

- You might not say that if you witnessed the several hundred Geiger counts/second you get from an old Aero-Ektar..... and on the other side of a lead brick too!

 

Likewise a 14" Cooke Apotal repro lens. Both use Thorium doped glass. But a consumer grade SLR lens? Maybe not so hot.

 

The particle count shown in the link above could easily be exceeded by pointing the detector at a pair of well-worn socks.

Edited by rodeo_joe|1
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On the other hand there's Cobalt-Thorium G

:rolleyes:

 

- Actually not too far from the truth JDM. Thorium 232 itself is an alpha emitter, but among its daughter products is a gamma emitter. So while Thorium-glass lenses were moderately harmless when new, in that their alpha emmission was easily stopped by air or a thin metal lenscap; over time the decay products build up to present quite a gamma-ray hazard that'll pass through almost anything.

 

Those old Aero Ektar and Apotal lenses were produced over 70 years ago now, and have turned into quite nasty gamma emitters.

 

There's just a slight underestimation of timescale in that Dr Strangelove clip. The half-life of Thorium 232 is over 14 billion years!

Edited by rodeo_joe|1
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