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Post by Peter S. on Mar 16, 2010 14:58:09 GMT -5
We have first results from a MC W.Rokkor 2.5/28. I haven't seen the raw data, but the guy, who took the measurement said it, the gamma spectrum proved that Thorium and its decay products had been found.
This is in line with my expectations, as I could not believe, that unwanted impurities could come into the glass in a percentage enough to have such an massive effect. We will measure two of my lenses, two 2.5/28 and one 1.2/58, and I will report the findings, too.
Furthermore I will test whether a 365nm UV LED is capable to clear that yellowish 1.2/58, which is a very nice short grip Rokkor (Berg&Tal), that was a pity if not used, at least occasionally.
Best regards Peter
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Post by pompiere on Mar 17, 2010 6:27:08 GMT -5
I now have a Pentax 1.4 Super Multi Coated lens that I can test. It was pretty yellowed when I got it, but I left it on a sunny window ledge for a month and it has cleared up. I've been pretty busy at work lately so it may be a little while before I can check it out. We have some pretty good equipment at work, but I may not get my lens back if I take it there.
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