Thanks JJ Chan for your extensive review, both in pics and text.
Today I first met a Milvus 50/2 and, incredibly, in the second-hand department of Photo Cirque in Paris. So I tested it. Compared with the predecessor :
- approximately same size and weight, but the lens shade is enormous (predecessor had a very narrow one). Given the deeply recessed front lens, I guess I am not going to use it very often
- there is a gasket at the mount: nice, but why such a conspicuous blue? Zeiss visual ID??
- aperture ring: clicks are too soft and too close to each other (half stops, over a short throw), so it is difficult to set aperture by touch; the predecessor was better and the micro Nikkor 55/2.8 even better
- sharpness, very low CA, low LoCA, excellent bokeh were preserved
- the tendency of the predecessor to underexpose at f/2 is no longer noticeable
- flare on stopping down is still a bit there, but decent now : great
Bottom line : I bought it... poor bank account...