Please note: PK lenses will align with their index mark at about 2o'clock instead of 12 o'clock.
This is to avoid the PK rear lens actuators clashing with the electrical contacts in the EOS body.
This will not affect the operation or the result.

The length of the lens actuators, height and length of the rear element shroud, and the protrusion of the rear lens element may cause problems with full frame digital bodies.