Quote Originally Posted by AgX View Post
I did not refer to the mirror (maybe the mirror-lock up will not release automatically after exposure, I don't know), but to that 4mm to contain the distance from film to shutter and the shutter itself.
Yeah, I didn't elaborate properly. What I meant was, the SWC has no mirror, so the 38 Biogon is fairly close to the film plane. How close, i don't know, but 2-20mm is probably the ballpark. The SWC has a leaf-shutter for taking the exposure, but I don't know if it has a rear focal-plane 'protection shutter' so the rear element isn't exposed when you change backs.
(afaik the regular hassy 500s have a focal-plane 'protection shutter', but that's more for protecting the film against light leaks when the leaf shutter is open for focussing. The SWC wouldn't have that problem so i don't know if they bothered putting them on).
Either way, 4mm sounds (to me) enough to at least get a 'protection shutter' in between the 50mm and the film, or you just have to be careful with exposed elements when you change backs. Otherwise it should work quite well in the same way as the SWC, no mirror, just a mount straight to a film back.