We have received some information from one of our sources that has seen the camera, and described it to us. He mentioned that EF lenses mounted directly onto the camera body.
We have been told in the past, that this will have a mount with a sexy solution for EF lenses, so we're going to hypothesize a bit about what we think it just may be based upon some patent applications we have seen recently.
In this patent application, Canon describes a mount that supports two different lens protocols. This is further described in these two patent applications where they discuss switching the lens mount to support two different protocols.
From this information, it's a working theory that the RF and EF mount will differ slightly and EF lenses will mount on the RF mount and cause it to “switch” to the EF protocol. If you mount an RF lens, it will switch back to the native RF protocol to support the lens. Interestingly, this locks the RF mount up into Canon's patent portfolio which will make it difficult for third party mount adapters to support on other camera bodies.
Right now the information coming from sources is extremely vague. Canon is keeping this completely under wraps like no other release that we've seen in the past. This may be entirely conjecture, and may not actually be what Canon is doing, but at this point in time, it sounds like a plausible scenario.
As a sexy fix for EF lenses, someone wrote about a moveable sensor which would be really interesting but I don't understand why an adapter wouldn't work.
Why wouldn't it work? A Canon adapter, made by Canon for Canon, would work flawlessly and be extremely fast.
Canon would then have a new future-proof mount and the adapter would make all or their EF lenses work.
Is there really a reason to have a native EF mount (or an EF-R with an EF flange distance) on a Canon mirrorless? If so, what is it?
You'd need some really bizarre rear lens caps for RF lenses if that's how they're designed, but so be it.
Let's face it. Canon has over 100 million reasons to use the EF mount and continue using it. Shortening the registration distance only improves a couple of handful of lenses. Canon RF lenses sound like they have a different (faster) lens protocol and ALSO could sit back into the mirrorbox similar to EF-S lenses.
Again, this was a hypothesis based upon the limited information we have and patent applications that were released.
How could you get the mechanical sensor moving reliably for say 10,000 movements?
Someone came up with an idea, and someone else a graphic to illustrate it, of EF fitting normally and RF lenses having the rear element/s protruding into the camera body.
This way you retain 100% adaptor-less compatibility with EF lenses and RF lenses can still benefit from getting closer to the sensor & have a small(er) camera+lens size.
I don't know enough to have any idea whether this will restrict potential designs for RF lenses.
The only drawback I can see is the camera body won't be able to be as slim as sony/nikon. But that's only a drawback for those who care about a thin camera body.
IBIS systems imply that it is already possible, it's more a question of logistics. Realistically, the same mechanisms that drive the focus group in the lens could drive the sensor plane as well, as long as there are flex cables attached to everything. And those systems actuate far more frequently. Part of the new lens protocol could be a key value to position the sensor. That would open up the lens design for any flange distance that is optimal for the lens, not forcing them to use one constant one for everything.
Guess 2: Lens Approach -- All RF lenses will have a rear element that extends back towards the sensor once mounted. The basic EF mount stays the same. If a future new lens doesn't need the inward-extending element it will simply be designed as an EF lens. (I don't think telephotos, long zooms, or Big Whites will need the inward extending element, so they will be EF lenses now and in the future). (If an RF lens is mountable at all on a regular EF mount camera it wouldn't hurt anything; the inward-extending element would not deploy, and would not be harmed.)
Guess 1 adds the cost of handling RF lenses to the mount on every camera sold, and I'm thinking the unit cost might be a problematic, but may be workable. Guess 2 shifts the cost of accommodating close approach to the sensor to each lens that needs it, but the cost may be even higher, and flexibility of lens design may be hindered somewhat.
My guess now is Guess 2, the in-lens approach.
Final note: Forget mounting APS-c EF-M lenses on the new full frame RF camera. Not workable. Not gonna happen (without an adapter, which won't be coming from Canon).
I guess we'll know next Wednesday!
So long as the camera body itself is lighter I think that's enough. It won't be as convenient as an EOS M but even 1lb off the weight would be great for carrying it around on a trip. Presumably there'd then be a slow migration to the (presumably) smaller/lighter RF lenses.