[Brightcolours]

I don't get it. Shall I take those posts seriously, Frank and Rover? One wants 8mm more focal length, the other a bit faster aperture, no matter if it's usable. Those f/1.2 do come from the days when Film was really highspeed with around 6400 ISO. And grainy like a field of rocks. Or one of those early sensors which went beyond 1600 ISO.


With contemporary sensors,

• who needs f/1.2
  
• and is able to focus that properly
  
• and is willing to leave resolution, contrast and flare resistance completely on a mediocre side?
  

• I like f1.2, or even more f1.0 (but that is too expensive). Why? For DOF freedom. 
  
• A Canon 6D/5D mkIII/ 1D-X has no problem focussing a Canon EF 50mm f1.2 L USM.
  
• My Nikkor-S*C 55mm f1.2 is sharp enough at f1.2. It is also contrasty enough when not shooting against backlight. My Canon FL 55mm f1.2 gives very nice flares against back light/low sun, something many photographers will appreciate. A reason to keep it as specialty lens, for sure.
  

any idea why Nikon didn't, nor Zeiss with their latest "around 50mm" lenses? Certainly the price was no limit.

Yes, I have an idea why. Nikon F-mount diameter is too narrow to make a real f1.2 lens. All the 58/55/50mm f1.2 lenses Nikon has made have had trouble with this, with extreme cats eye highlights/bokeh discs as a result and because of that also a lot of loss of light. And swirling bokeh. There simply is not enough room mount-wise for f1.2 for a standard prime. 

The Canon EOS mount diamter is a lot larger (54mm vs. 44mm), providing room for bigger back elements. Both my 55mm f1.2's have way too small back elements. The difference to the Canon EF 50mm f1.2 L USM is big (and very noticable).

 

For Zeiss it is the same situation. If they were to design an f1.2 with large enough back elements, it would not fit Nikon F-mount. And Zeiss does not design EOS mount only lenses.