A hypothesis concerning the RF mount

[streestandtheatres]

Can someone explain to me why a mirrorless camera can't just have an EF mount? Why can't it be a camera that's like the current cameras, but mirrorless?
With all the great EF lenses, what's the advantage of a new mount?

 

[Talys]

As long as I can mount an EF lens onto an RF mount without an adapter and not lose core functionality, I will be a very happy person, and I will consider RF a "sexy" solution.

Since I have no issue with the size of EF lenses, and have no desire for smaller lenses for my ILC's, everything else (the benefits of RF, whatever they may be) is just gravy.

 

[3kramd5]

Can someone explain to me why a mirrorless camera can't just have an EF mount? Why can't it be a camera that's like the current cameras, but mirrorless?
With all the great EF lenses, what's the advantage of a new mount?

Perhaps new communications protocol which requires a different interface.

Otherwise: selling new lenses.

 

[dak723]

I completely understand your point, but in ten years, when most (?) people will have moved to mirrorless (imo), how will people react when they see the limitations of that retro-compatibility? Will people now criticize Canon for that decision?
I'm guessing Canon won't reinvent a completely new mount in just 10 years right?

I'm nowhere near an expert on the subject so keep in mind I'm just speculating here. But I think it's a mistake to limit the future because of the current/past. If Canon keeps that flange distance on their new mount, then every mirrorless camera in the next 20-30 years will be bigger for no reason.
[EDIT] I know size is not the only advantage of mirrorless but for many people, it is one important aspect.

You make it sound like a camera with the same flange distance can't be made considerably smaller. It can. The EF flange distance only keeps the size the same in one direction - the depth. If you want a decent grip, then the depth dimension won't change much anyway. Height and width can be made much smaller as witness the difference between the SL-1 and other Canon DSLRs.

 

[Timedog]

What if RF lenses have an another moving element, like the rear element or something, that focuses the light on a closer plane. I don't know anything about lens design, is this possible?

Then they could update their lenses to this new design, while keeping a thicker body for now, and then come out with the thin body a few years from now, with a bunch of lenses that'll work on thin body. At some even later point, when thick body cameras are phased out, they could stop making lenses with the extra moving part.

This idea I'm sure sounds idiotic, and probably isn't even physically possible, but no solution really sounds good right now

 

[ahsanford]

Can someone explain to me why a mirrorless camera can't just have an EF mount? Why can't it be a camera that's like the current cameras, but mirrorless?
With all the great EF lenses, what's the advantage of a new mount?

1) The market (at least a good portion of it) wants smaller gear -- it's easier to differentiate on the market as different/new/better than something that looks the same as the last camera.

2) If they go thin, it unlocks the potential to go adapt lenses.

3) Potentially ring USM, STM, etc. are not ideal for DPAF (it's fine but not as quick as OVF / AF array SLR folks use) and some future communication protocol from lens to camera is required to drive lens as quickly as with an SLR.

- A

 

[streestandtheatres]

Perhaps new communications protocol which requires a different interface.

Otherwise: selling new lenses.

Ah, that makes sense, I guess, good for Canon but not so good for those of us with a few lenses that we like!

 

[ahsanford]

You make it sound like a camera with the same flange distance can't be made considerably smaller. It can. The EF flange distance only keeps the size the same in one direction - the depth. If you want a decent grip, then the depth dimension won't change much anyway. Height and width can be made much smaller as witness the difference between the SL-1 and other Canon DSLRs.

+1. See yellow open box + shaded yellow box on far right. It could be that small.

- A

 

[3kramd5]

Ah, that makes sense, I guess, good for Canon but not so good for those of us with a few lenses that we like!

Only if a new mount means those lenses you like cease to function, which it unlikely.

 

[3kramd5]

While a dual VF may be a bit of a kludge, I think I’d take one rather than trade away the advantages the mirror brings.

Full disclosure - I'm not a graphic artist (obviously), but here's the idea. Imagine proximity sensors, one per VF. Bring your eye near the top one, and the mirror goes down for optical VF and off-sensor low light AF goodness. Bring your eye near the side one, and the mirror locks up for sensor-based AF tracking, WYSIWY(kinda)G viewfinding, etc.

I think they'd earn my money just for trying.

 

[dak723]

....
Now is Canon's chance. Sony and Nikon have both demonstrated the engineering benefits and the market acceptance of some sort of mount change/optimization.

Perhaps there is market acceptance or perhaps the marketing is so pervasive that what is best no longer matters and people will be duped into buying anything "new" and "innovative." Those engineering benefits that Sony introduced with their 18mm flange distance are enough to have convinced me that if Canon has a similar new mount, I won't be buying any new FF mirrorless. Unlike many here, I can not afford to buy the top level lenses Sony lenses, so when I bought the A7 II, I could only afford their kit lens (a not so cheap kit lens, mind you - and their other 28-70 kit lens has reviews that are similar to my experience). And those lenses are probably the worst performing lenses I have ever bought - having very poor performance away from the center. After further study and speculation, it is very likely the short flange distance that was the cause.

So that engineering benefit of a drastically reduced flange distance may sway some, but will prevent me from going mirrorless FF unless some technological progress has been made to improve performance.

 

[dak723]

Can someone explain to me why a mirrorless camera can't just have an EF mount? Why can't it be a camera that's like the current cameras, but mirrorless?
With all the great EF lenses, what's the advantage of a new mount?

A new mirrorless can indeed just have an EF mount. It could be exactly like the current DSLRs, only mirrorless. There seem to be many folks who would like just such a camera.

And there seem to be many who want the smaller size that a new mount could bring.

That is the qaundary. Which group is bigger. And can Canon somehow satisfy both groups.

 

[bergstrom]

nikon got abashing for the new mirrorless having ond sd slot, so are we going to get deja vu and hear everyone bashing canon now for the same thing. Shouldn't they hold off revealing it and producing it,until they put 2x sd card slots in it and that will shut some people up.

 

[neuroanatomist]

Food for thought...

Sony couldn't compete with CaNikon in the DLSR market, so they pivoted to APS-C mirrorless. They saw Canon coming with APS-C MILCs, and shifted focus to FF MILCs.

Nikon had been losing ILC share for some time, saw an opportunity in mirrorless, and brought out the Nikon 1...which flopped. Time passed.

Canon has been for >15 years and remains the ILC market leader, currently by a huge margin with nearly 50% share. They entered APS-C mirrorless and have had major commercial success in that segment.

So, Sony and Nikon are in the FF MILC space from places of relative weakness, whereas Canon is going there from a position of strength. To me, that means Canon has quite a bit of freedom in their approach. The other two players need to take customers from Canon, which neither has been able to do successfully, even with 'better sensors' and the only FF MILCs (Leica notwithstanding). Canon isn't likely going to take many customers from Sony and Nikon, holding their share is still a win, meaning their main target for FF MILCs are current Canon ILC owners. To me, that means Canon will make choices that appeal to their current base. A FF MILC with a native EF mount may be that path.

 

[Richard CR]

A new mirrorless can indeed just have an EF mount. It could be exactly like the current DSLRs, only mirrorless. There seem to be many folks who would like just such a camera.

And there seem to be many who want the smaller size that a new mount could bring.

That is the qaundary. Which group is bigger. And can Canon somehow satisfy both groups.

I'm curious .. how much smaller do you want it? the rumors suggest slightly bigger than the M50.
that's around SL2 sized, so quite small.

 

[tmroper]

Maybe it'll be something like my Mamiya 6's 50mm lens. The camera's lens mount is pretty far away from the film plane, and the back part of the 50 reaches pretty far back into body (the back of the lens looks kinda like a rocket nozzle). I don't know why they're designed that way, but with this idea in mind, the Canon RF lenses could do a similar thing, and have the mount part way up the barrel, leaving a back part to reach into the body and closer to the sensor.

 

[scyrene]

Scrap EF mount in favour of the long term benefits

Remind me, aside from slightly smaller/maybe easier-designed and cheaper lenses for wide angle, what are those benefits?

 

[scyrene]

Not so needlessly, full compatibility with all those EF lenses.

Not to mention better ergonomics with big lenses, which seems mostly ignored in these dicussions!

 

[scyrene]

1) The market (at least a good portion of it) wants smaller gear -- it's easier to differentiate on the market as different/new/better than something that looks the same as the last camera.

2) If they go thin, it unlocks the potential to go adapt lenses.

3) Potentially ring USM, STM, etc. are not ideal for DPAF (it's fine but not as quick as OVF / AF array SLR folks use) and some future communication protocol from lens to camera is required to drive lens as quickly as with an SLR.

- A

I understand you want to be fair to all concerned, but I think you're running the risk of overstating the case here. 1. We don't know how much of the market wants this (not enough to say 'a good portion of'), though it may indeed be the case. But you yourself have shown in diagrams how for FF, once most lenses are attached, there's not much size difference. It would be reasonable for Canon to say 'if you want small, go APS-C', though I'm not predicting whether they will. 2. People further up the thread have reminded us that you can already adapt lenses for EF - though some are notably impossible, like FD. 3. Is there any evidence this is coupled to a new mount?

 

[stevewhitemd]

Can someone explain to me why a mirrorless camera can't just have an EF mount? Why can't it be a camera that's like the current cameras, but mirrorless?
With all the great EF lenses, what's the advantage of a new mount?

Three reasons:

One: flange distance, that is, the distance from the back end of the lens to the sensor. For the EF lens that is 46mm. That allows the lens to clear the mirror on a DSLR. Importantly, that's the distance that the throw of light from the lens focuses -- on the sensor, where it should. Change that distance and the lens no longer throws the light to focus on the sensor.

So on a mirror-less camera, you'd need to support a flange distance of 46mm to use the EF lens. But that MILC camera doesn't NEED 46mm, because there's no mirror to accommodate. One of the appeals of a MILC is a smaller, lighter camera. Building it to accommodate the EF lens is a problem.

Two: that long flange distance creates another problem, that is, the design of the lens. Particularly for a wide-angle lens, to throw the light onto the sensor becomes difficult, and the design required to do that is complex -- therefore heavy and expensive. Notice how light an EF-M lens is? With the short flange distance (I think 15mm for that series), it turns out that the lens design becomes simpler, therefore lighter and less expensive (yes, you could make it some heavier with weather sealing, construction, etc., and since you're Canon you could always, always make it more expensive).

Three: the width of the mount, that is, the hole in the body where you attach the lens. On an MILC you can make that wider; that means (potentially, all other things being equal) you can have lenses with larger apertures. The new Nikon 50mm f/0.95 S series lens is an example.

So in a new MILC it's really, really tempting to design a new lens series. You can, because of the fact that you have room, design an adapter for the EF lens, much like the EFM adapter for the M series cameras. All that does is connect the lens electronically and reset the flange distance to 46mm. If Canon has a new R series camera, their choices are 1) forsake the EF series (not happening), 2) find a way to mount the EF lenses natively (that's the issue here) and 3) use an adapter (like the M series).