The Tektronix Series 125 f1.9 is a lens originally designed for photographing oscilloscope screens, so it's not exactly well adapted for life outside the lab: it's kind of bulky, has threads all over the place, and would take a bit of doing to mount it to a board (there's no retaining ring). Focal length is probably around 75mm, though it's hard to find specs for these sorts of things; coverage is at least "full frame", though it'll likely cover medium format, too. The Ilex/Elgeet No.3 X Universal shutter works well, with speeds from 1s to 1/100s. Could be fun.