The diameters of EFM and RF mounts

Started 1 month ago | Polls thread
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lumenite Senior Member • Posts: 1,177
The diameters of EFM and RF mounts

In my opinion, Canon's first decision as to the diameter of EFM mount was a mistake. They must have thought that the mount was good enough against M43 kingdoms or Sony E mount. Moreover they must have not been serious with mirrorless system at the moment since APS-C market has not been their main target. It seems certain that they just wanted to defend the market with the minimum effort. Finally they had to develop another mount, which is RF with 54mm diameter, while the diameter of EFM is 47mm.

Sony E mount is 47mm wide; Leica L, 51mm; Nikon Z 55mm. All of them support both full frame and APS-C sensors. Now RF appears to want to support both as well. At this moment, I think Canon had made another mistake when they released RF. The mount looks too big to be shared with APS C bodies since they have to give up small form factor. Considering Sony's latest lenses, I doubt Canon and Nikon's argument for a bigger mount. Canon must have thought that they would use RF only for fullframe and they needed a totally new, better mount for their future.

Would Canon really have chosen 54mm if they had not had EFM?

Although RF is not good for compact APSC bodies and Canon maybe has to give up EOS M, I think, however, Canon would not be able to avoid using RF for APSC bodies in the end. It is a better mount in terms of technology, and their focus has been always on fullframe market, apart from the inefficiency of keeping two mounts.

What do you think? Which of the following would be the best solution?

 lumenite's gear list:lumenite's gear list
Canon EOS-1D Canon EOS M Canon EOS M5 Canon EF 28mm f/1.8 USM Canon EF 50mm F1.4 USM +7 more
separate mounts for APSC and Fullframe like Canon as of today: dedicated mounts!
23.1% 6  votes
one big mount like Nikon Z: just focus on FF since FF is the answer.
38.5% 10  votes
one small mount like Sony E: good enough even for FF and wonderful for APSC.
19.2% 5  votes
one medium sized?
19.2% 5  votes
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