12-09-2016, 11:11 PM
I wouldn't worry about the Lanthanum.
It is used in modern optical glass requirigng high refraction UD elements and such.
Metabones, who ground their glass in the USA, use it amongst others in their Speed Boosters. I reckon they would only do so if they can adhere to the USA standards, which, as far as I know, are quite rigorous when it comes to radioactivity.
BTW, Metabones are the same guys who design and manufacture special lenses for the police forces (Infrared, UV etc.)
Kind regards, Wim
It is used in modern optical glass requirigng high refraction UD elements and such.
Metabones, who ground their glass in the USA, use it amongst others in their Speed Boosters. I reckon they would only do so if they can adhere to the USA standards, which, as far as I know, are quite rigorous when it comes to radioactivity.
BTW, Metabones are the same guys who design and manufacture special lenses for the police forces (Infrared, UV etc.)
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....