I have the new LN50 lens with a cs-mount and I think there may be a problem with the lens mount threads. I can’t screw the lens into the mount more than half a turn, which leaves most of the threads exposed and the lens seems to be unable to focus. Should the lens be able to screw up so it is flush with the camera adapter base? I also tried attaching the CS-C adapter to the lens and it behaves the same way, indicating that the lens may be having the thread problem fitting properly.
I bought the lens through Amazon.