for sonnar copy, you may consider canon 50/1.5. See benny photos for more reference! Somehow, canon 50/1.5 (ltm) is cheaper than nikkor 50/1.4 (ltm). Both lenses have similar results except nikkor 50/1.4 @ 1.4 has special glow effect. Both lenses are cooler results than zeiss 50/1.5.
but that is a non-original conversion. (seems to be using a summarit mount). RF coupling accuracy could be way off. and min. focusing distance could be much more than 1m. so beware!