Recentty My frient Marco Cavina bought in Italy a MR-2 lens forZorki/FED without the usual KMZ logo. We see here the lens mounted in a Leia IIIf with a Zeiss 21mm finder.
Together we see a comparison with Jupiter 12 and Orion 15 lenses. every lens is technically described at quality results on Russian lenses from my friend Marco Cavina.
http://www.luciolepri.it/lc2/marcocavina/articoli_fotografici/Soviet_and_wide_lenses_on_Leica_M/00_p.htm