B&W Lens

I remember measuring the radioactivity from an alpha emitter and Paper being effective in blocking it.

 

I remember that too! Also those small chambers with Acetone vapour, IIRC Wilson's Cloud Chambers ?? You could actually see the ionization tracks!

 

So, if you rest the Thorium glass lens on a piece of film or photo paper (in the dark!) will it make an image or does reciprocity failure kill such fun?

 

If so, how about a digital sensor where reciprocity failure isn't an issue?

 

I've got a ex-RAF Tritium dial from a WWII bomber, it's half life has rendered it a no-glo area!!

 

I may try and see if an extended exposure through a 35mm Series E reveals anything...:-)

I remember our teacher being obliged to be very careful with an alpha emitter, then waving the gieger counter over an old watch he had in a cupboard (which had radioactive phosphorescence) and showing it was much more radioactive than anything we got allowed near. Then again, I remember one of our class experimenting with mercury, then going up to the teacher and saying "this stuff is weird, isn't it?" while poking a ball bearing in his hand and popping it in his mouth; the teacher's reaction was fairly priceless. It was a change from most of our teachers, who'd blow up capacitors and set of a fire extinguisher in someone's pocket for entertainment.

 

I vaguely wonder whether a radioactive front element could be useful for macro photography if the subject has some phosphorescence - you'd get better front lighting than a ring light (presumably equivalent to putting a half mirror with a side light in the optical path).

 

For what it's worth, I was listening to a podcast last night on the subject of small refracting telescopes, and pointing out that a good achromatic doublet (ideally with exotic glass) can outperform some apochromatic triplets - but particularly, that a fast doublet refractor is useful for narrow-band astrophotography (primarily on a monochrome sensor) and can be made a lot cheaper for its size than something with good apochromatic correction, so long as you refocus after changing the filters. Apparently some are sold specifically for this. So technically, that's a "lens that's good for B&W imaging". I've got to say that a 6" achromatic refractor looks to be a lot cheaper than a 600mm f/4...

I've read (decades ago) that someone put a hot-glass lens on photographic paper for a few days and it exposed the paper. With the Summicron- probably need to put it front-element down. Although I know and understand that the radiation is not going to get through the rear elements, I do not leave the Hot Glass lenses on my digital cameras when not shooting with them. I converted a Super-Tak 50/1.4 to Leica M-Mount, made an RF cam for it. I bleached out the yellowing with the UV Lamp.