Cibafan wrote:
I do not know if the lens I have is the short barrel or not, but it is a manual focus F mount 135mm f2.8. The length is 4-5/8 inches from front edge to rear not including mounting ring.
The lens in question is a 135 f/4.0 Nikkor-Q bellows lens, with no focusing mount. It actually is a close-up ("Micro?") lens from Nikon's rangefinder programme, and does not have an F mount.