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Minolta 50mm and radioactivity question

Started Feb 25, 2018 | Discussions thread
Magnus Wedberg Regular Member • Posts: 114
Re: Minolta 50mm and radioactivity question

Camerapedia says these lenses can contain thorium:

  1. Minolta MC W. Rokkor-SI 1:2.5 28mm (early variant, before radioactive glass impurity could be banned)
  2. Minolta MC Rokkor-PG 1:1.2 58mm (early variant, before radioactive glass impurity could be banned)
  3. Minolta MC Rokkor 1:1.7 85mm (the earliest variant of the MC line) http://www.dg77.net/photo/x500/mc85.htm

I have the 28/2.5 although I have never used it, and I know it's radioactive as it has the classic yellowing. I also have the 58/1.2 MC Rokkor-PG, but it has not yellowed and is probably not radioactive.  I ALSO have the MC 85/1.7, of an early version with metal focusing ring, and that one is slightly yellowed, probably a thorium lens too.

I have not come across many Minolta lenses with visible yellowing so they are probably quite rare. I wouldn't worry about it. I actually have three thoriated lenses; the third is a Takumar 55/1.4, that one is noticeably yellowed and it didn't improve after half a year of non-stop blacklight treatment.

Regarding lenses. The 50/2 is very good, light, and overall a complete steal. Most manufacturers 50/1.7-2 are very good, these optical formulas have been used for many decades and are actually still used, the new Sony 50/1.8 FE is probably the very latest incarnation of these designs -- it's basically a classic SLR lens with a longer barrel.

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