Originally Posted by jaapv
The Summicron 40 (Please don't adopt that nasty cron and lux habit
) is exactly as good as the Summicron 35 version iv, so there is no real reason to prefer the latter. Personally I think that it is one of the most if not the most suitable lens for an M8. The minor drawbacks that it has a weird filter thread, brings up 50mm frame lines and needs to be coded by a third party cane be overcome with very little problems; Heavystar sells a series 5.5-39mm adapter and hood, any technician can adapt the mount for 35 (perfectly suited framelines too) and coding is not really needed.
The Summicron-C 40mm len is excellent, but if you can find a Minolta M-Rokkor 40mm f/2, generation II, it is an even better performer due to multicoating. AND it has the easy to find filters for JIS 40.5mm filter thread.
(The Summicron-C 40 was made by Leitz for the CL, the M-Rokkor 40 was the exact same design manufactured by Minolta for the Leitz/Minolta branded CL. The generation II model was the same lens, with multicoating, released for the Minolta CLE. I've had all three, and the M-Rokkor 40mm II is the best performer of the bunch: less flare.)