I just bought a lens I've wanted for a long time, a SA 65 mm. It is from the la te 60's in a Synchro-Compur. I can't figure out how to open the shutter for foc ussing. There is a B setting but no T setting, and no little lever like on my o ther lenses to keep the shutter open for this purpose. Did there use to be one, and somebody removed it or broke it off? I can see no place where it used to b e. So do I need to hold the release down in "B" then to focus? Not a terrible problem except I can't get a shutter release in my home-made recessed lens board . . ..