Roger Hicks , Nov 24, 2005; 10:02 a.m.
Having used the 50/1.5 Nokton with most Bessas (R, R2, R3A, T) I'd back the M3 hands down: I have really not been very happy with my own focus accuracy with the Nokton at full bore on the R3A, whereas I had no problems with even a 50/1 Noctilux on M-series (MP and M4-P). Both the actual base length and the effective base length of Ms are significantly greater and I've certainly found it easier. Others may disagree.
Actually I'd go for an M2 but that's another argument.