fullstop said:
Canon EF-M mount might possibly be "force-fit" for FF [similar to Sony E-mount, involving major design compromises], but it was definitely developed for APS-C only and not with FF in mind. At least that's what the Canon people in charge of EOS M / EF-M said.
- Where is the most important factor in developing a new mount called "EF - M"?
Nakamura: It is a mount diameter that satisfies the APS - C size image circle properly, but also to make it possible to realize small size and light weight. In addition, the operation feeling such as attaching and detaching the lens is designed to be the same as the EF mount.
- EF-M mount. The mount diameter is also reduced from the EF mount
Can the EF-M mount correspond to sensors larger than APS - C size, eg 35 mm full size sensor?
Kikuchi: I think that I can not do that. I can not say that if I do something strange, I will not physically enter ... .... It is a level that the amount of marginal light falls considerably or that you do not know what the image will look like.
http://dc.watch.impress.co.jp/docs/news/20120810_551672.html
Exactly! It’s just too small.
Look, if Canon wants to replace their top pro cameras, and they said that they did, just not yet, then they need to have the very best possible mount, not a compromise.
I’m tired of reading that mirrorless means smaller and lighter. There’s nothing wrong with the bigger, and heavier Pro camera bodies now. Many of us prefer that size and weight class.
But to compromise from the very beginning, limits everything for the future. When, eventually, I replace my 5Dmk IV with mirrorless, I want to replace it with something that will be comfortable with my bigger tele’s. We all know that big lenses on small bodies aren’t a good match. So Canon should make something robust.
Canon also makes small, and light DSLRs with the current mount. That means they can do it with a bigger mirrorless mount too. I wouldn’t even argue if they kept the current mount.