Thanks all. I learned a lot.

"KM" wrote in message
...
I was cleaning my RZ and began wondering why each lens must incorporate
its
own leaf shutter, then began wondering why we find leaf shutters only in
lenses. I understand why the shutter has to be in the lens for rangefinder
systems (proxmity of wide-angle rear elements to focal plane =
insufficient
space), but why couldn't they be incorporated into SLR bodies?

In current leaf-shutter systems like the Bronica ETR and Mamiya RB/RZ,
doing
so would make the lenses smaller and lighter. In focal-plane systems like
the Pentax 645N, you'd get flash synch at any speed.

I'm sure there's a perfectly good explanation I'm overlooking.What is it?