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. 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.

You're describing what would sound good to us, and not what would work best for Canon's bottom line.

Myself, I can certainly see Canon's logic. Why sell just one lens line when you can sell two! Or threee! It's brilliant!

Why sell three lens lines when you can sell a single lens line three times.

That's complete babble.  I've used my (same) EF 85mm f/1.8 on every body line so far.  I did not buy it threee times.

Having multiple lens lines is a lot more challenging when your sales volume gets cut in half over just three years.

Sales volume is determined by the products you make available.  Just ask Coke or Pepsi, or Tide for that matter.

They must have thought that the mount was good enough against M43 kingdoms or Sony E mount.

Absolutely.

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.

This is exactly right. Plus it's been super-popular to boot!

It is still outsold by the EF mount.

And the EF mount is dead.

Finally they had to develop another mount, which is RF with 54mm diameter, while the diameter of EFM is 47mm.

The RF mount much better accommodates Full Frame Mirrorless. It was a natural progression.

Sony E mount is 47mm wide; Leica L, 51mm; Nikon Z 55mm. All of them support both full frame and APS-C sensors.

Except Canon and Nikon now aren't locked into an inferior mount. They have that big wide throat to work with.

It definitely makes it easier, but Sony seems to be coping just fine.

Sony was the first to "cook" their corners.  It's become ingrained in their design now.  Canon and Nikon now do the same, but to better effect (IMHO).

Now RF appears to want to support both as well.

So? It costs them next to nothing to develop a couple of cheapo RF-S lenses. As some have mentioned, they could even basically re-run a couple of EF-M designs with a new mount!

At this moment, I think Canon had made another mistake when they released RF.

Not me. I've been shooting with Canon RF for almost 2 years now, and it's magnificent.

The mount looks too big to be shared with APS C bodies since they have to give up small form factor.

Thus EOS-M! It was viable back with EF, and it's still viable with RF on the scene. I'm living proof! Vive le 'M!! Vive le 'M!!

Let me know when you can mount a RF lens on a M system body.

Don't have any desire to.  I love my EF-M lenses.  All of them.

And I love my RF lenses on my R bodies.  (actually proves my point)

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.

Again, it can be used for both FF and crop. Just like EF was. For minimal expenditure.

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

Certainly. It allows for improved lens designs!

It is also the same diameter as the old EF mount.

EF is dead.

Although RF is not good for compact APSC bodies and Canon maybe has to give up EOS M

Canon might (might!) give up on EOS-M, but we don't have to.

I think, however, Canon would not be able to avoid using RF for APSC bodies in the end.

Right. Why develop another APS-C mount when it's not needed.

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.

EOS-M is operating all in The Black for Canon. Even an M6 Mark III "firmware upgrade" would cost them next to nothing.

The same could also be said for the entire EF-S lineup of bodies and lenses.

They're all dead too.  And sooner than EF-M.

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

The best solution depends on what you're shooting, and how. IMHO it's great to have a number of excellent choices... Rather than the other way around.

Great for the consumer, but not so great for manufacturing efficiency and Canon's bottom line.

Actually my argument is that it's good for both!  Horizontal market saturation!  Squeeze everybody else off the shelf!  Works.

R2