[obican]

The mount diameter of Sony NEX is the same (tiny bit smaller). That explains why Sony needed a different mount for FF mirrorless....  :ph34r:

I have not read anywhere Canon stating what you state above?

 

The numbers: Fuji X-mount diameter: 44mm. Nikon F-mount diameter: 44mm (bigger flange distance). Leica M39 diameter: obviously smaller than 39mm diameter (bigger flange distance), Leica M mount diameter 44mm (bigger flange distance). 46.1mm for Sony E mount. 47mm for Canon EOS M mount (54mm for EOS (bigger flange distance)).

 

That said, both the Nikon F-mount and the Sony E mount are rather narrow and kinda limiting for large apertures. 

 

 

Slightly trivial info:

 

Nikon F mount and Sony E mount are almost completely the same thing. You can fit made-for-E-mount things like adapter tubes and body caps on to a Nikon and it will go in and will even click-lock in place (although with a slight wobble). Trick is, it's about 120 degrees rotated. I don't recommend putting F mount lenses directly in front of a Sony though since protruding pins might damage your camera but even the rear lens caps are mostly interchangable.