Casual testing of a $39 Industar 50 collapsible lens (Tessar type, made 1965) on the N-7.
(Yes, the empty hay shed has that lean. ))
Rather surprised by the sharpness (looking at the pine trunks in the middle distance). Other close up work reveals outstanding sharpness, too.
Hand held (I said 'casual').
UPDATE: I bought two of these, the other made in 1959 at a different factory S-E of Moscow. So far I've not been able to see any difference in results whatsoever.
UPDATE 2: Very surprised this has been looked at 17 times let alone 1,700 or more times. Hope others have had favourable results, too.