Zeiss C Sonnar 1.5 50mm is probably the best lens for Black n White "classic soft wide open look".
The is a focus shift issue which you need to get used to which can get you great results. Basically, "focus on the ears to get the eyes" method.
Compared to Lux pre-ASPH, Sonnar is alot cheaper. More bang for buck.
Sonnar is at least 3 lens rolled into one. If you read read reviews you will know why. At different apertures, Sonnar exhibits different characteristics. Wide open it is a "classic" lens, but at smaller aperture it becomes very sharp modern lens.
Sonnar is also small form factor. It is small. Not a big ass heavy lens.
I highly recommend it if you want a 50mm, especially if you want to do BlacknWhite.
I'm not really a fan of Sonnar for color photo.
I beg to differ, the C Sonnar is amazing for colour photo! It renders very vibrant and vivid colours. I use mine mainly for colour shots.