The diameters of EFM and RF mounts

nnowak wrote:

R2D2 wrote:

lumenite wrote:

In my opinion, Canon's first decision as to the diameter of EFM mount was a mistake.

Mistake? You mis-read Asian corporate culture methinks. A smaller M-Mount was part of their plan all along. They think in the Loooong term.

Yes, Japanese companies tend to take a very long term outlook, but there are clear mistakes in the design of the EF-M mount that suggest that Canon did not anticipate a future with professional level full frame mirrorless.

Even beside the size of the eos-M mount there's more evidence this is the real mistake of Canon.  Canon should have launched the R6 and R5 before at the same time as the launch A7III.  Even the R was significantly later launched as the A7III, and as the first model of the RF line this is clearly a product of a company not thinking forward enough.

Right now Canon is on par as it comes to sensor tech.  The big question is if Canon can follow Sony if it's doing a next round sensor upgrades.  Is the Canon tax we pay enough to finance new sensor fabs? Or will Canon lay back again leaving the owners of RF L glass without sensor upgrades?  Beware of doing "investments".  "Investments" might give ROI for the next 5 or even 3 years only if you love the best sensor tech.

Comparing the FE 50mm f/1.2 G-master to the RF 50mm f/1.2 L the bigger RF mount doesn't give an advantage for optical designs of lenses. I'm not sure if a bit better IBIS is enough to justify the size of the RF mount.  So I would argue the M mount probably isn't too small, I would rather argue the R mount was both too late to the show AND too big. With the RF mount you can't make a camera more compact than the A7C. With the FE mount you can. It's not only the weakness of the M mount (being too small for full frame)  forcing Canon to create the RF mount, it's also the weakness of the RF mount (being too big) to make truly compact cameras forcing Canon to sustain the M mount.

There's a lot of speculation of discontinuation of the M mount. At the end of the day the M50II and the M200 are at least available. Go try to by an A6100 or A6400.  It's nice when a mount is shared with full frame so we all should assume aps-c would last forever in the Sony world, however, if you can't buy it these kind of eternities won't bring you much.....

Making the mount just a couple millimeters larger would have allowed EF-M to fit a full frame sensor. If EF-M and RF flange distances were changed by only a couple millimeter, adapting RF lenses to M bodies would have been possible.