Rob-F
Likes Leicas
It's doubtful I can contribute much to this erudite discussion, as much of it is over my head already. I did work for an AEC contractor in Nevada in a former life, though-- over 40 years ago. I don't remember much, but I recall that Beta radiation is particles, and they can only travel a maximum of 2 and a half inches from their source. Also, they are stopped by any material placed in their way.
Since this thread is in reference to the M8, am I correct in presuming we are talking about the collapsible Summicron? This next observation is something I learned on the internet, so approach it with caution: I understand that the radioactive element in the Summicron is not the rear element, but the one before it; and the rear element is a leaded glass; and that this was done to reduce the radiation reaching the film (or the sensor, in today's terms). And the Beta from the radioactive element would be completely blocked by the rear element. None of this would set aside any concerns, I don't suppose, about the X-ray radiation (which I only just learned about from reading the above).
I can tell you this: I have two collapsible Summicrons, one in bayonet mount, the other in screw mount. If I place them on my light table, I can see the slight yellow color. But I can shoot Velvia, and the color rendition in the slides is acceptable and agreeable. I suppose the degree of yellowing is about like an 81A warming filter--in that while it's there, and it's real, it is quite mild, and within a range often used for balancing color. Hmm, I ought to compare my Crons to my warming filters--might be interesting.
Since this thread is in reference to the M8, am I correct in presuming we are talking about the collapsible Summicron? This next observation is something I learned on the internet, so approach it with caution: I understand that the radioactive element in the Summicron is not the rear element, but the one before it; and the rear element is a leaded glass; and that this was done to reduce the radiation reaching the film (or the sensor, in today's terms). And the Beta from the radioactive element would be completely blocked by the rear element. None of this would set aside any concerns, I don't suppose, about the X-ray radiation (which I only just learned about from reading the above).
I can tell you this: I have two collapsible Summicrons, one in bayonet mount, the other in screw mount. If I place them on my light table, I can see the slight yellow color. But I can shoot Velvia, and the color rendition in the slides is acceptable and agreeable. I suppose the degree of yellowing is about like an 81A warming filter--in that while it's there, and it's real, it is quite mild, and within a range often used for balancing color. Hmm, I ought to compare my Crons to my warming filters--might be interesting.
