Because of all the uncertainties I decided to ship the camera with the lens to Nikon. The technician phoned me and said that mirrorbox, mirror and optical paths are in perfect conditions (Only the on/off switch needs to be replaced which has nothing to do with the issue I have). The technician, however, does not know much about the Zeiss Planar and cannot give any advice on that.
Yes, I used a different lens for architecture: Distagon 2/25 which was sharp. Very sharp. But I cannot remember the aperatures I used.
I used the Planar 1.4/50 basically between f2.8 and 4. What you are saying, if I understoos you correctly, I should look for a different screen that is optimized for fast lenses. RIght? The camera now is equipped with a K Screen. The prizm will turn black by 4-56. Once the camera is back from Nikon, I will try the Marko-Planar 2/50. (This will be my new portrait lens, I hope, since it has a classic design and less focus shift than the 1.4/50 planar).
