takumar 50/1.4 (8 elements) vs Nikkor-S 50/1.4 Auto

[Erik Lund]

Indeed some of the old MF Nikkors are susceptible to Galling due to the aluminum design, however it's an extremely unlikely situation that only occur if the lens is damaged ie. bent out of shape by a big impact. In all normal conditions the lubrication will prevent Galling of the threads even if the lubricant stiffens up over the decades.
However, newer re-assemble a lens without lubrication, to test fit or the like, you will do irreversibly damage to the threads immediately   

[mxbianco]

Both lenses in this comparison are known for having radioactive thorium in some lens elements, which over time become browner and browner...

See this article, where some Nikkors are also having numerical radioactivity levels: https://camerapedia.fandom.com/wiki/Radioactive_lenses
Nikkor-S 50/1.4 has a level of 178 μSv/h, and BTW the Noct-Nikkor has a greater radioactivity level (211 μSv/h front, 183 back)

Not a big deal, you get more radiation by having a CAT scan or an international plane flight, but can you confirm the brownish color?

Ciao from Massimo

[richardHaw]

the 8-elements takumar isnt thoriated to my knowledge, i am not sure about the nikkor but i doubt

i am in the process of bleaching my 35/1.4, it's going to take more than 72 hours on this one