Is there any M-mount radioactive Summicron 50/2 ?

[frame-it]

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28 minutes ago, AndreasG said:

What happens with the shutter curtains, do you close the aperture?

wide open usually, on SL/SL2S, not actually pointing it towards the sun or anything

Edited September 5, 2022 by frame-it

[Anbaric]

1 hour ago, wlaidlaw said:

I have been told that the yellow discolouration can be "cured" by shining a very powerful UV light through the lens for an hour or so. That seems a bit unlikely to me as I assume the discolouration is a chemical or isotopic change in the composition of the glass, resulting from being struck by alpha particles from the thorium. If isotopic change, I cannot see the mechanism by which UV light would change that back.

This is apparently the mechanism of the discolouration:

https://www.sealandair.fr/pdf/birns-nucleaire/camera-lights/radiation-induced-discoloration.pdf

Presumably there is enough energy in UV/visible light to give the electrons a kick and clear the colour centres?