Quote Originally Posted by Les Sarile View Post
The original Asahi Pentax was the prototype of all SLRs that followed.

Close, but some Germans beat them!

You see, back in 1954 Wirgin introduced their Edixa Reflex:

It had lever wind on the right side. Film reminder dial around the rewind. The typical bottom location of the film rewind button, and the centered tripod socket... The prism was interchangeable though and Wirgin introduced automatic aperture operation in 1956... it took a while for Pentax to adopt. Of course the Pentax had an instant return mirror and the Edixa didn't.

The Edixa is oddly forgotten today. Kind of like how people forget Topcon's contributions to the development of the SLR.