Keith over at Northlight Images, always a voice of reason has written an opinion piece about Canon's new RF mount and how it might affect Canon going forward. He also addressed EOS M and the EF-M mount.
From Northlight Images:
We’re all doomed – or not
Already I’m seeing articles and comments about Canon’s move to the RF mount that are not even wrong in their level of their cluelessness about optics and the camera market(s) around the world.
The sky is not falling – perhaps some context and history will help. In a few years all will be well, but probably better ;-)
Canon lens mounts – A brief history
Canon changes lens mounts and systems – some people are left behind, some move on. With the new RF mount, there are many questions as to what it means for different categories of Canon camera user. This note aims to show a bit of historical context for the change – noting that past changes didn’t have the echo chamber of the internet to contend with…
I’ll mention some of the older lens mounts first, since many modern DSLR users may not even know this aspect of Canon’s lens history. Read the full article
If you switch from mirror to mirrorless you can keep all of your lenses, for me that's all that matters.
How knows, maybe EF-M is dead and Canon will come up with a new RF-M mount which is 100% compatible.
All I want to know, if I eventually go down this path, is if I can use RF lenses on an EF-M body.
In a word, no.
The other direction can be argued similarly. Really, why buy the latest most expensive premium FF glass, pay even more for a fiddly adapter ring (if that would be possible, but it's not) and then put it on much cheaper and smaller camera (that probably won't get any bigger or get dual sd or a bigger battery) instead of EF (or EF-S) lenses that can be bought for less money and with lower cost adapters?
It can't be mounted, otherwise they could just skip the 32/1.4 EF-M in favour of the 35/1.8 RF with IS
There are cases where it makes sense to put FF glass on a crop body. This is not it.
It was annoying for some people not to be able to mount EF-S glass for the cropped 4k video, but that has been eliminated (and with optional filters added in for good measure)
I don't see it as something you'd build a system around, but if you have both systems it's convenient to be able to bring some things over.
And I can't see that much point anyway if you can't use the same batteries for instance. I think there will be an M5 Mark II later on, but the body will remain the same.
The limitation was not created now, not at all. It was created with the EF-M in the first place. But it also has advantages of being able to remain compact and light.
Looking at the bigger picture, it is not that big part of their overall market and even if it was compatible, I don't think people would buy these big heavy and expensive lenses for it (ok no price yet, but we'll see).
It just seems odd to build the most robust lens lineup available only to loosen the grip on that advantage over the competition unless it is for the long-term good. Sure, EF is still functional using the adapter, but if users are willing to use an adapter to mount EF to RF, then it isn't as much of a reach to mount EF to E or Z.
Don't get me wrong, I'm on board for a compact full frame kit but I just don't understand the decision yet. Hopefully we'll know more tomorrow!
Yes, you can use EF lenses on the E-mount if you need features that the Sony offers that's a given. Like FF 4k or higher framerates, built-in IS, dual cards slots (for now) but loosing the DPAF is a biggie, not to mention the color output and general handling with the touchscreen, etc.
But overall it will be way, way better on an EOS R body in the same way that Sony lenses are way better on the Sony body (having dual stabilisation working together seamlessly).
So if you are not a tripod shooter, this system jumping doesn't make that much sense. At least manual lenses with a decent adapter won't have problems on any of these cameras.
And while watching DRTV in the old days, I've learnt that you can interchange camera straps as well.
I am interested in the new FF mirrorless and already have the M5. I would say that they both will serve a different purpose and will get equal use. When I want small and conveneient, I will take the M5. When I want maximum quality, I will take the R. The M5 is so much smaller and lighter, it will still serve a very big purpose for many, in my opinion. I would have absolutely no interest in using lenses for one system on the other. RF lenses will be way to big and heavy for the M5.
I think there are no tea leaves to read yet. I do not think that Canon is thinking of this as a transition - at least not yet. For now, mirrorless is just another alternative. I don't think DSLRs and EF lenses are going away any time soon.
That's what Canon have been trying to achieve with the widening of their product range, and there are professionals who have many different tools, where one one thing does slightly better than the other, at least now I see cameras as being way more universal than they used to (and yet they still try to limit and segmentate them as much as they can while at the same time pricing them according to their functionality)
I would be very surprised to see this new camera at the 2000$ mark, when I think it as more of a Z7 competitor.
I'm hoping that Canon provides some comment on the future of the RF mount - obviously they mean business if they're offering lenses not currently available in EF - that incentivizes transition to the alternative system. I'd love to hear the justification for mount transition - it may give us an idea of the type of gear they plan on releasing in the next several years, and where RF is headed.
For me, I am becoming more and more interested in an EOS R as a backup to my 5D IV, but the more I think about it the more I wonder if the next body would result in the 5D IV being the backup to whatever comes next.
...Then again, my GAS could use a break too!
EDIT: as an aside, it will be interesting to see what Panasonic do with their rumoured full frame system (due to be 'pre-announced' on 25th September) and how it will relate to their existing m4/3 system.
okay, well that's a personal belief. It doesn't really negate that somebody else may legitimately want to buy a 7D and eventually a 5D or 1DX without necesarily owning everything in between, or likewise an M50 and then whatever R body suits them. It also doesn't negate the backup body argument as some suggested where you don't sell your cropped sensor camera, but keep it as a second body before you can get a second FF body. Simply driving over people's concerns with the good old: "go out and shoot with what you have" cliché is ok but does not invalidate the concerns. In particular when it is their money, not yours that they will spend.
Adapting the mechanical and various complexities of the undocumented F protocol to sony is the problem more than routing the cables from the bottom of the adapter to the top. So the experiences with the F-E adapter are irrelevant as it pertains to the Z mount. How many adapters will be made for Z and R mounts depends more on the willingness of either company to be open about the protocols, or the ability of the reverse engineering team. The reason sony chose to open up the specs is because contact routing, machining, etc, are not as difficult to get right because of the state of electronics and precision part manufacturing today, in particular for cases where you're adapting a mount of similar size but that it sits much farther way from the sensor. There is plenty of room.
Said that, I think an EF-Z adapter is a given because it would be very popular and capitalize on people's willingness to adapt things these days, including its target customer: Z buyer, who is adapting lenses anyway. I imagine metabones and others are just waiting to get their hands on Z bodies and lenses to evaluate the Z protocol and reverse it. They already understand canon's EF, and given both Z and EF are fully electronic, they don't have to worry about weird links, levers, screws, etc that are such a pain in the F mount.
That's the only variation that's actually plausible, although it still really doesn't make much sense apart for tripod use and the makers of lens adaptors, it's good business for them.
Even if they adapt it super well, is it going to be function any better than F-mount lenses, having better than 3-axis stabilization? No. But unlike those, will they support dual IS? No. Will they work like with DPAF? No, not even close. Is it going to be better for video overall? Probably not for 95% of the people and the rest have other choices than the EOS R.
Sony is supporting this idea because they didn't really have much choice and now it is simply better to use a native lens but they still sell cameras.
Nikon on the other hand sells other cameras and wants to sell lenses (any types that they make) and XQD cards.