[gofour3]

Yes they have yellowed, not to the degree of the older takumars though.
The counts are the same as the takumars.

I was checking the s/n database and the K50/1.4 seems to have two groups of serial numbers:

10xxxxx
15xxxxx

Yours and my K50/1.4 are both in the 15xxxxx range. I have no way to check mine for radiation, but have not noticed any yellowing yet. (Will check tonight)

Wondering if the yellowing K50/1.4's could be limited to the one s/n range?

Phil.

[lmd91343]

Condor,

I am sorry to hear of your tragedy also. Your uncle and my father-in-law worked as an engineer and research scientist in the pursuit of making us safer. We will never know if their work helped accomplish that. Maybe it did. Maybe it was of no use like when the army stocked up on horse saddles after the First World War. Thankfully their work did not fail in that regard. We did not exchange nuclear weapon blows with the Soviet Union. Your uncle's service to our country is honorable and laudable.

Our relatives were exceedingly knowledgeable in ionizing radiation, more so than probably any of us here on this list. They succumbed to the danger of which they were among the best experts in the world while taking the best precautions.

As scientists we know, based on statistics, what levels of exposure correlate to cancer. The charts and statistics are well known.

We also know that it takes ONLY ONE energized particle to hit a chromosome in the right spot to cause a cancerous growth. On average it may take "one million" of those energized particles passing through you to have that terrible single hit. Will it be the first or the "millionth" hit?

It's just odds. Like deaths in automobile travel. Will you be killed in your first time driving? Or will you have a "million" trips before a fatal accident. I lost a 16 yo friend and a 60 yo uncle to car accidents. Each had a vastly different number of trips under their belt.

As for me, several years ago I cleared the yellow from both my SMC Tak 50/1.4 and Canon chrome nose concave 35/2.0 by the sunlight trick. Both were exceptional lenses. Upon realizing that five of the daughter products in the thorium decay chain (decaying thru 13 radioactive isotopes before reaching stable non-radioactive lead) produces beta radiation as opposed to the safer alpha, I disposed of those beautiful lenses. Oh that chrome nose concave lens!

From my scientific education and background, I know and understand the odds and dangers. I don't want to expose myself to dangers, even small ones, if they can be avoided. Remember, it is one of a "million" hits that would cause a cancer, not the cumulative effect of one "million" hits.

Sincerely,
Lance

P.S. I use million as a substitute for a very large number.

P.P.S. Sorry for the long rant.

P.P.P.S. Beta radiation can pass thru several millimeters of metal and alpha is stopped by human skin or paper.

Lance,
I'm sorry to hear that.

My uncle died in 2009 after working there 20 way plus years. He was some type of engineer but was secretive about what type.

He was a contractor the contract was bought and sold many times. Martin Marietta and battele I remember.

There was also a separate claim in regards to his work with nuclear weapons in Russia ( he developed some weird parasite or something ). This was all sponsored by DOE.

I do not know the amount that part of the family is kinda secret about it. I was told " if you die of cancer and worked at place x during time y the amount was predetermined ". That was for oak ridge. It does not include Russia.

I don't know how much he was making but I can't imagine not six figures but not plural. Even with an insurance amortization of 62-68 discounted back for present net value it has to be north of $500k. That is a guess.

There was another claim on his work in Russia just to be clear.

Purple Heart in Vietnam. Great person. An inspiration to me.

[jkomp316]

We also know that it takes ONLY ONE energized particle to hit a chromosome in the right spot to cause a cancerous growth. On average it may take "one million" of those energized particles passing through you to have that terrible single hit. Will it be the first or the "millionth" hit?.