That is my problem Didier, my R-D1 is Spot-on with my Lux 75 at close up and infinity, however can see a slight effect of focus drift at mid-distance, and my Cron 35 front focuses a little bit, while my Nokton 50 backfocuses a little bit, since both the cron and nokton focusing are within the depth of field, I decided to leave everything as it is.
It looks like lenses don't all focus exactly the same way, but more likely they focus the same way within a set tolerance, and with very fast apertures the effects of such tolerance can be seen.