Hi,
The previous posters have covered most of details regarding the J-9, but I will summarize:
- Been in production since shortly after WWII
- Based on Zeiss Sonnar design and tooling
- Several different manufacturers over the years. The current maker is LZOS.
- Made in several mounts including M-39, M-42, and Russian bayonet
- Early versions are all "silver"
- Later versions are black enamel
- Black versions labeled "MC" are multi-coated, other black versions may be single or multi-coated. Silver versions are assumed to have some sort of coating.
- M-39 versions often have mechanical issues
- Even MC versions are flare-prone and should be used with a hood
There has been discussion on various forums regarding early vs. later J-9s. I know of one user on this forum (carpents) that has owned both silver and black versions. My take on the matter is that since build quality has been an issue with the various Russian/Soviet lenses, I would try and find one of recent manufacture (black) that has been gently used. I would also suggest the MC version. It is also worth noting that the J-9 pictures that have been posted to this site have all (to the best of my knowledge) been taken with late-manufacture black versions.
Steve