Originally posted by RawheaD I think it is physically impossible to make a 30/1.0 lens for a PK mount camera, irregardless of how big you make the primary element. I think it's impossible to make a 50/1.0 lens for a PK mount camera. The register is too long (and the mount opening is too narrow).
I believe the Canon mounts (EF for sure, I don't know about FD) are the only ones for SLR with a register short enough and mount opening wide enough to barely make a 50/1.0 possible. Obviously, shorter the focal length the harder it gets (because of the register), so a 30/1.0 is not possible even on EF, let alone PK.
Somebody correct me if I'm wrong (just learned about this principle recently ;-)
I'm pretty sure there was a 1.0 Noct-Nikkor back in the Seventies, actually, I forget the FL.
I'd be pretty surprised to see a 1.0 lens coming out at this point in history: high-ISO performance is getting better and is a turn of the dial away: lenses that wide open are invariably pretty soft, and the viewing advantage doesn't count for nearly as much with good AF available. (frankly, with a lot of the screens out these days, the brightening means you don't see visible differences in the finder faster than a certain point, anyway. )