The best years with consistent performance: KMZ, 1951 through 1955. Early 1956, but need to inspect the rear triplet for being German. I have a 1956 KMZ J-3, 56003xx, as good as my wartime Sonnar. Then picked up the 56040xx- "what went wrong". It is a new optical formula, uses Russian glass and I believe they were trying to reduce focus shift due to spherical aberration. That worked, at the expense of everything else?
ZOMZ: 1958 through to 1962, best consistent performance. Some 1957 are good, but I've seen more variation. I have one from 1956, 56002xx. "They were still getting the kinks out of their design and implementation".
ZOMZ- I have a very sharp 1975 that is as good as the KMZ: it required a change to the shim, looked like it had never been used. It is noticeably better than others I've shot with. Porbably upper 5% or so?
Valdai- I went through a dozen to find a good one, and it required major work. I replaced the front element with one from a 1960s ZOMZ, made it better. If you get a Valdai J-3, be sure to have an inspection period.
I have a Jupiter-3 made from the parts of 4 lenses, 1950 KMZ barrel, 1952 front element and middle triplet, rear triplet from a 1930s Sonnar. An acquired taste.
Nikki by
fiftyonepointsix, on Flickr