How about a thread for the very interesting lenses from Eastern Europe, up to the Urals?
These are from a (new) Helios 40-2, an 85mm f/1.5 lens I received for Christmas (cross-posted):
All are wide open. Nothing here is critically sharp, so Otus-lovers can look the other way, but everything is IMO sufficiently sharp... The one of me is pretty much at MFD.
If you can find a Jupiter-3 from a camera forum that has been tested- best to go that way. The marketplace here, Leicaplace.com, rangefinderforum.com, getdpi.com.
The Jupiter-3 is made to the Zeiss Spec, and usually needs to be adjusted for a Leica. Even with a mirrorless camera, often needs to be adjusted to focus to infinity. It's not hard, but these lenses can be a can of worms. A forum member sent me a 1950 J-3 to work on, focus was WAY off. Someone had cemented it into the focus mount- most likely used JB-Weld. Usually not that bad, but Ebay and Russian lenses can be a crap-shoot.