I've an old TTA aerial lens (WWII vintage) that I'd like to mount on my 2D. But finding a ring/nut has been nigh impossible. So the options are ... (1) If you have a ring that you know fits, I'm interested ... or (2) Anyone got one of those aperture mounts available @ a modest price? As far as shutter, I'll probably construct a Jim Galli type. They're cheap and quite reliable.