[wim]

I don't see the issue, to be frank. A mount does not cost much. So they can go either the Sony route and use the narrow APS-C mirrorless mount and make do with that, or they make a new mount. Either way, they need to make FF mirrorless lenses.

 

No one is going to buy a Sigma style "mirrorless" which actually is a DSLR without mirror, really...

Light fall off for most uses simply can be corrected. And MFT with similarly big apertures will show similar vignetting (APS-C too).

 

What I mean with a new mount is not just the new mount, but also the fact that new lenses need to be designed and manufactured. Considering that the FF market is relatively small compared to APS-C etc., and that the market for higher grade cameras (higher than phone based cams) seems to be dwindling, I doubt Canon will start investing in an FF mirrorless system soon.

 

Can they do it? I am sure. Will they? I do not think they will in the current market.

 

As to vignetting: the short flange distance in principle makes vignetting worse, due to light rays with higher angles of incidence reaching the edges of a sensor. This will likely be worse with FF mirroless than with smaller size sensor based mirrorless cameras, as the flange distance needs to be kept much smaller relatively speaking. In addition, high megapixel numbers make this worse, due to the construction of current series sensors. And yes, this could be autocorrected, even on a per lens basis, but it increases noise to start with, and probably also amplifies other faults, lens faults f.e.

 

Kind regards, Wim