50 1.2 focusing.
I didn't read every reply but I have been down this road.
F 1.2 lenses 50 or otherwise have no trouble being focused on an SLR that has its mirror in alignment/. Mirror alignment is most critical with any wide-aperture lens.
That being said, I think I have had mirror alignment issues with ONE of the some 25 Nikon bodies I have used.
The 50 f 1.2 is not very useful to my tastes used wide open. The 1.4 and 1.8 and early 2.0's are sharper wide open and don't suffer from coma and pincushion.
I am a pro... I haven't owned a "wide" 50mm for my Nikon kit for some 10 years.
The 55 micro AIS f.2.8 Nikor is the sharpest lens in my Nikon kit. I find it funny that I owned a 50 1.2 only to trade the heavy beast for a 50mm f1.4 Af... traded that because it just wasn't used much at all and now the 55 and 105.1.8 both AIS (NOT AF) are the most used lenses with my AF kit.
Take this to the bank from a full time professional.... if you chose the 1.2 have fun.. it's not all bad... just not to my "Zeiss' tastes. It's pretty soft used wide open and so damn heavy.
PS don't even think about using it without a hood... and please don't put a protective filter (skylight etc) over these highly corrected lenses...