# Patent: EF/EF-S Adaptor For Canon Full Frame Mirrorless



## Canon Rumors Guy (Jun 26, 2015)

```
A patent showing an EF/EF-S adaptor for a full frame mirrorless from Canon has appeared. There is a switch on the adaptor to go between EF and EF-S lenses.</p>
<p>Patent Publication No. 2015-118208 (Google Translated)</p>
<ul>
<li>Published 2015.6.25</li>
<li>Filing date 2013.12.18</li>
</ul>
<p>Canon patents</p>
<ul>
<li>Flange back is shorter body</li>
<li>Flange back is long, a lens having the same image circle as the image pickup device body</li>
<li>Flange back is long, a lens with a smaller image circle than the image pickup device body</li>
<li>Mount adapter to change the diameter of the flare cut stop, depending on the image circle of mounting the lens</li>
</ul>
```


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## neuroanatomist (Jun 26, 2015)

As I stated previously, the EOS M was Canon dipping their toes into the tepid MILC waters. They're clearly getting ready in case the water warms up enough for a comfortable swim.


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## rrcphoto (Jun 26, 2015)

that's a bizzare patent.

I've read the full patent more than once, and I"m not thinking this is for a canon mirrorless, but for canon to make an adapter that allows for lenses with even smaller image circles to be used on a full frame sensor.

for example - an ef-s lens could be used via this adapter to cover the entire image circle of a full frame camera.

or using this adapter, canon could make even smaller lenses as they would share this common adapter.

it's novel - but highly impractical.


https://www4.j-platpat.inpit.go.jp/cgi-bin/tran_web_cgi_ejje?u=http://www4.j-platpat.inpit.go.jp/eng/translation/201506260920265738977610407618955930EC8C3EA95EDA4F3E51CD2CC98C482

the full patent application (keep in mind this is simply an application, not a published patent).


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## dolina (Jun 26, 2015)

So is the SLR dead?

My take it is their hedging for the future where SLRs are as relevant as RF.

I give it say 2-3 decades.

As more people's first camera will tend to be mirrorless and smartphones Canon has to keep relevant.


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## Mr1Dx (Jun 26, 2015)

1. Wonder if this has to do with EF line working well on other camera companies?
2. Canon sees mirrorless will take bigger bite in near future?

Regardless, having more choices in FF mirrorless will be great for photographers.


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## Macoose (Jun 26, 2015)

In general, what would be the approximate time frame for something like this to come to market?

Just curious.


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## wsmith96 (Jun 26, 2015)

Would it be funny if this adapter was to be for canon products to be mounted on other manufacturers mirrorless cameras. If they made a canon product that was supported to connect and operate say, on a sony camera - they could cut the legs right out from under sony's lens business. Glass is where the money is right?


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## dcm (Jun 26, 2015)

Macoose said:


> In general, what would be the approximate time frame for something like this to come to market?
> 
> Just curious.



Sometime between now and never. ;D

It really depends on the situation. I've built products where we waited until the last minute before we announced to file to cloak what we were doing as long as possible and maximize the protection period. Filing early would give away product plans for the first product in a new line. In other cases we've filed defensive patents that we had no plans to build at the time, but wanted to stake out the territory before someone else did. You do this to keep your options open for the future on an existing product, otherwise a competitor can file a patent that shuts down an avenue you might wish to pursue later.


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## KeithBreazeal (Jun 26, 2015)

Canon APS-C EF Converter by Keith Breazeal, on Flickr


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## weixing (Jun 26, 2015)

Hi,


KeithBreazeal said:


> Canon APS-C EF Converter by Keith Breazeal, on Flickr


 You forget to put the white dot for EF-S lens. ;D

Have a nice day.


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## Haydn1971 (Jun 26, 2015)

Had to happen at some point - although I'd expect the EF range of lenses to continue as they are - essentially just without the mirror - you don't have to have a small form factor for So I'd see this as another line for Canon, for large albeit niche small form factor FFML camera - a EOS-Mx for want of a better name.


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## Maximilian (Jun 26, 2015)

So finally the FF MILC game has become interesting to Canon. 



Haydn1971 said:


> Had to happen at some point - although I'd expect the EF range of lenses to continue as they are - essentially just without the mirror - you don't have to have a small form factor for So I'd see this as another line for Canon, for large albeit niche small form factor FFML camera - a EOS-Mx for want of a better name.


I think you're quite right. 
Only point against this might be, that there could be some things optimized in body to lens intercommunication. 
Otherwise you wouldn't notice differences in AF between EF/-S and EF-M lenses on EOS M.
But this could be built into futur EF/-S lenses.


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## Mt Spokane Photography (Jun 26, 2015)

It is a adapter, and obviously adapts a EF-s or EF lens to a FF mirrorless camera. It has a adjustment to baffle the smaller image circle of a EF-s lens. As usual, the translation leaves you guessing at a few words.

From the Patent Document:

"In recent years, the mirror loess camera system which has an image sensor of 35-mm film size is proposed for the further high-definition-izing, and the intermediate adapter which can equip with the interchangeable lens for single-lens reflex cameras is called for. The size of the opening of the intermediate adapter in this case turns into a size which secures the light flux at the time of equipping with the interchangeable lens for 35-mm film sizes. Wearing of the interchangeable lens which secures the image circle of APS-C size to the camera which has an image sensor of 35-mm film size will be attained via an intermediate adapter."


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## WorkonSunday (Jun 26, 2015)

filing date 2013 <-- surely this is not the only piece in development, they sure kept the whole FF mirrorless development programme quiet!


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## PepeSilvia (Jun 26, 2015)

As far as I can see it doesn't specifically state that the body is mirrorless (correct me if I'm wrong), or that the "smaller image circle" lens is EF-S or APS-C, what if this is for adapting full frame EF lenses for a medium format digital body in development?


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## mb66energy (Jun 26, 2015)

I think this is some research about "what is possible".

The adaptor length is roughly 120mm if I interpret the image correctly:
- lens is mounted on the lower end (large positive group)
- the camera is shown on the upper end (with sensor plane marked)
- the adaptable light blocker has an additional housing (upper end, right sided box)

The EF-S 60mm 2.8 is a very good lens but the EF 100mm beats it easily on full frame. So where is the point to mount EF-S lenses on a FF mirrorless? And the cost of such an adapter might be in the region of 500-1000 $/€ - more expensive than replacing e.g. the EF-S 60mm with the mentioned FF counterpart.


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## meywd (Jun 26, 2015)

mb66energy said:


> I think this is some research about "what is possible".
> 
> The adaptor length is roughly 120mm if I interpret the image correctly:
> - lens is mounted on the lower end (large positive group)
> ...



What if you have a bunch of EF-S lenses, then the cost will be less, and I doubt it to be in that price range, don't think it would be more expensive than the 2xTC III


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## mistaspeedy (Jun 26, 2015)

Canon should make a speed booster for their EOS M mirrorless camera.
What else would be interesting is a speed booster for APS-C cameras. Putting a full frame lens on an APS-C body should gather more light.


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## 9VIII (Jun 26, 2015)

Adapting crop lenses to a full frame sensor doesn't make any sense. You'd end up with a maximum aperture darker than f8 on many lenses. I can't see anyone actually wanting to use it.

Converting full frame lenses to a crop sensor, however, is highly appealing. It has practical advantages you can't achieve any other way and gets crop shooters to buy more glass.

If Canon is making their own Speed Booster (Negative Teleconverter?) this could be very good, except that I've been saying for years that they should just be building EF-S lenses with the focal length reducer built in and undoubtedly that would give better results.


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## infared (Jun 26, 2015)

LMAOROTF...HA...ha..ha...hee...hee...hee...
Oh..forgive me...oh...let me catch my breath....phew...the words "Canon" and Mirrorless" in the same sentence just...WOW...it JUST REALLY MAKES ME LAUGH...!!!!


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## mistaspeedy (Jun 26, 2015)

Yeah... I haven't really seen any lenses exploit the fact that APS-C sensors are smaller and they could make the lenses faster by a stop.

For example... instead of the full frame 50mm F1.8 STM, they could make a APS-C 50mm F1.2 STM (one stop faster) - for the same $125 price - this is key!
40mm F2.8 full frame pancake? make it a F2.0 for APS-C for the same price.
Same thing goes for various other lenses.

However, it seems that Sigma have finally brought something to the table with the:
Sigma 18-35mm f/1.8 DC HSM Art Lens for Canon... a fixed F1.8 through the whole focal length.
However, at $800 it is wildly expensive.


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## Khufu (Jun 26, 2015)

I enjoy looking at these diagrammes regardless of accompanying text/interpretations and seeing what comes to me 

When I look at this, whether correct or way off I'm inclined to conclude I'm looking at:

1) A MIRROR, right? That trapezoid block in the middle, with the hinge looking bits at the top? Maybe?

2) M4/3 and APS-C MASKS with MOTOR: far right, for motor. One mask in light path, other to the right towards motor. Relative to apparent "mirror" size these appear to be approx M4/3 and APS-C, if not APS-C and APS-H, though relative sizing implies the former to me.

Keith et al; yeah, I was thinking we're in "Mirrorless Focal Multiplying" territory, hey, that's a teleconverter!... alas, the prototype you've acquired may require space-sharing by lens and adapter elements and photon teleportation to hit everything in the right order  ...your conclusion seems fairly sound though, re: teleconverting EF-S!

I'm inclined to believe Canon are covering bases before third parties attempt the same thing - this all seems like unlikely to make it to market (more lens elements to diffuse little light sparingly? Meh) but we could spend days debating potential uses...

Okay, having said all that, I'm going to actually read some of the patent info now, then I'll be back to apologise for my earlier, silly assumptions once I know what's really going on here 

rrcphoto: thank you for the link, much appreciated! Do you keep on top of these things, generally know where you're looking to find patent info etc? Just curious - I don't know if it's easily done or not but thanks!

Neuro: Aye, unfortunately for interested minorities it's often the case that the big players aren't too interested in mildly-profitable yet exciting endeavours... and it's fair to say they'll shy away from will:won't it bets, like shipping M2 and M3s globally - but maaaybe Japan & (East?) Asia's enthusiasm towards the M and A7 series (serieses? English brainfail from Englishman..) can be enough to prompt at least an importable FF Eos M, daft EF-S adapters and all


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## Khufu (Jun 26, 2015)

...and I'm back, fork and alls, to eat my words 

Okay, so it's an elaborate EF & EF-S to FF adapter, with no optical/focal multiplying elements, incorporating a mask when EF-S lenses are attached; I can only imagine this is to preserve intended representation of the EF-S lenses' capabilities, without Canon being accused of making EF-S lenses with rubbish Full Frame qualities!

What I thought was maybe a mirror may simply be a door/cap, entirely covering the sensor during lens changes - either that, there's a third mask ooor there's only one mechanical mask which moves over to the shown STM to be adjusted or closed.

I don't love this excessive bit of hypothetical kit - if it's the only model Canon offer the simplistic third party sales should be healthy!


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## BRunner (Jun 26, 2015)

It looks too big for use with consumer mirrorless FF camera... Maybe for coming FF EOS Cinema camera? FF C500 mark II?


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## stefang (Jun 26, 2015)

It looks like the diagram displays a lens too.
Wouldn't it make sense that the adapter simply tells the camera whether a EF or EF-S lens is attached, forcing the camera into crop-mode in case of an EF-S lens?


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## e17paul (Jun 26, 2015)

Macoose said:


> In general, what would be the approximate time frame for something like this to come to market?
> 
> Just curious.



I'm sure that it could be immediate if Canon wanted, but will surely wait until the full frame Eos M comes along. That will only be when EVF technology has improved to Canon's satisfaction, and they have successfully developed it for their cameras. Electronic technology changes fast, but Im expecting Canon to take a little longer.

The Eos M mount is larger than the (full frame) Leica M and Sony FE mounts, so therefore allows for future full frame mirrorless cameras.


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## 9VIII (Jun 26, 2015)

mistaspeedy said:


> Yeah... I haven't really seen any lenses exploit the fact that APS-C sensors are smaller and they could make the lenses faster by a stop.
> 
> For example... instead of the full frame 50mm F1.8 STM, they could make a APS-C 50mm F1.2 STM (one stop faster) - for the same $125 price - this is key!
> 40mm F2.8 full frame pancake? make it a F2.0 for APS-C for the same price.
> ...



Unfortunately it's not quite that simple. Remember you're adding a focal length reducer, so to get your 50mmf1.2 you would have to start with an 80mm lens, it's going to be big to begin with but then you're also adding complexity to the formula. Look at the Zeiss Otis line for an example of the size of an unusually complex lens. I have no idea if a focal length reducer could be incorporated into the formula without adding elements. If it can, great, if not, you're adding another few hundred grams to an already large lens. The Canon 50mmf1.2 is 590 grams and the 85mmf1.8 is 425 grams, so you're probably pushing that above the weight of the 50f1.2 just to accomplish the same level of light gathering with a smaller sensor.
But remember the added complexity of the speed booster is probably going to reduce image quality, and that compounded by the reduced IQ from using a smaller sensor.
Which is not to say that it shouldn't be done, but it sounds like a challenge and there are big trade offs.

I get the impression that this sort of idea hasn't been tried before just because no-one thought that people would put up with having a 2lb 50mm lens before the Otis was announced. Zeiss actually used a retrofocusing design for a lens that's longer than the flange distance (retrofocus an optical trick that moves the focal plane and allows lenses to use a focal length shorter than the flange distance, on an SLR that's everything below 40mm [note that retrofocus has nothing to do with focal length reduction we're talking about]). The Otis design is totally redundant, but they managed to use the extra elements to their advantage. I'm assuming this sort of thing wouldn't be possible without computers.
The question for Canon would be something like "will crop shooters pay $1,500 or more for a 50mm lens?" But looking at what Sigma is doing, I have to wonder if they couldn't make something happen for under a grand.
I know I would pay $1,000 for a 2lb 50mmf1.2 equivalent crop sensor lens, but how many other people would is a good question.

Thus far companies like Fuji have opted to use larger normal apertures for their lenses, e.g. the 56mmf1.2.
The reason you don't see f1.0 lenses is that the circuitry on current sensors doesn't allow light gathering past a certain angle, so f1.0 is useless on digital bodies (http://www.dxomark.com/Reviews/F-stop-blues)
Fortunately we're on the brink of introducing Back Side Illumination, moving the circuitry to the other side of the sensor, which has the potential to improve things drastically.
(Yes, right now a large percentage of the sensor you look at when you take your lens off is circuitry and not light gathering pixels.)


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## DRR (Jun 26, 2015)

My theory, which I have floated around here multiple times -

EF-M is Canon's mount of the future for APS-C. Eventually all consumer level APS-C (rebels included) will go EF-M mount. There will be a "large" variant (Rebel Mirrorless) and a "compact" variant (current EOS-M). There will no longer be mirror box consumer cameras. There is already an existing EF/EF-S adapter for EF-M.

New FF Mirrorless mount in the future (EF-X for argument's sake). FF will eventually move to the new mount but with 100million EF lenses out there, Canon knows they need an adapter. So as native EF-X lenses are introduced, existing users are "kept in the Canon family" with a EF/EFS to EF-X adapter. This adapter basically adds the space back in, that Canon has taken out, by removing the mirror box. Of course EF-S lenses will produce an image circle that won't cover the whole sensor but that problem is pretty academic, and one that Nikon has already solved - in camera crop mode.


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## pedroesteban (Jun 26, 2015)

Since many people here don't have a background in technical drawings, let me help: 

- The "100" label shows the mirrorless camera
- The "102" label shows the adaptor
- The "101" label shows a lens mounted on the adaptor

As someone pointed out before, the adaptor comes with a housing for the EF/EF-S converter / mask. However, the adaptor length is about the same as the camera length.

Looks like a Canon FF mirrorles is coming. It wouldn't surprise me if Canon developed a satisfactory EVF and decided that the upcoming 1dx mk II, 5d mkIV or 6d mk II will be mirrorless. I'd bet on a mirrorless 6d mk II.


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## mb66energy (Jun 26, 2015)

stefang said:


> (1) It looks like the diagram displays a lens too.
> 
> (2) Wouldn't it make sense that the adapter simply tells the camera whether a EF or EF-S lens is attached, forcing the camera into crop-mode in case of an EF-S lens?



Ad (2): It would be easier to read the data stored in the lens which identifies the lens - if EF-S is part of it's name the camera knows it is an EF-S lens. So no adapter needed for this.

like pedroesteban written while I worte my post:
Ad (1): I quess you are right. I think the curly brackets on the left designate the body (100), the lens (101) and the adaptor itself (102). This explains the complex arrangement of lens groups with ~15 lenses which are supported by a complex mechanics.
The adaptor itself has two functions: To increase the flange distance between mirrorless body and EF/EF-S lens AND provides the option to choose between two diaphragms to cut out flare/vagbounding light depending on the image circle the lens has.
ADD: The lens might be the EF-S 55-250 mark i version - see the lens arrangement drawing under
http://cweb.canon.jp/ef/lineup/ef-s/ef-s55-250-f4-56is-stm/spec.html

So: no speed booster or anything like that. Just a clumsy device that helps to reduce non-wanted light of EF-S lenses on a FF sensor. I would solve the problem by a "baffle diaphragm" consisting of several blades which were adjusted to EF and EF-S lenses to keep the thing compact.


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## Andyx01 (Jun 26, 2015)

mistaspeedy said:


> Yeah... I haven't really seen any lenses exploit the fact that APS-C sensors are smaller and they could make the lenses faster by a stop.
> 
> For example... instead of the full frame 50mm F1.8 STM, they could make a APS-C 50mm F1.2 STM (one stop faster) - for the same $125 price - this is key!
> 40mm F2.8 full frame pancake? make it a F2.0 for APS-C for the same price.
> ...



When you compress an EF image circle to an EF-S size, you also effectively reduce the Focal length.
e.g. a 50mm 1.8 with a 0.625X TC would result in: 31mm f/1.1

An 85 f/1.8 on the other hand would be closer to what you are after: 53mm f/1.1

As far as adapting EF-S lenses to FF sensors, a 1.4TC is just 0.2x shy of doing just that - (however there is the obvious compatability issue with the shape of the mount.)

18-35 f/1.8 isn't really all that expensive considering:

24-70 f/2.8 ----0.625 TC'd---> 15-46 f/1.8

15-46 f/1.8 = $2000
18-35 f/1.8 = $800

That said, I don't beleive this "EF/EF-S Adaptor" is a converter, I think it's an "Adapter" just like it reads.


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## Famateur (Jun 26, 2015)

9VIII said:


> Adapting crop lenses to a full frame sensor doesn't make any sense.



I don't pretend to have any clue what Canon is planning, but I often hear people that are heavily invested in EF-S lenses and are ready to try full frame say, "I've got to sell all my lenses anyway, so I might as well consider switching systems." Having an adapter that would allow them to keep using their EF-S lenses might convince them to stay with Canon. That would make sense (at least to those who didn't plan ahead and buy EF lenses for their crop body).

As for full frame mirrorless from Canon, I think it's inevitable (if the competition continues to apply pressure) -- I just don't think it will be any time soon. At least several more years, in my opinion...


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## Famateur (Jun 26, 2015)

Khufu said:


> ...Asia's enthusiasm towards the M and A7 series (*serieses*? English brainfail from Englishman...



How Gollum would say it.


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## dak723 (Jun 26, 2015)

I think folks are way over-complicating things. Nor does it imply any new camera is immanent. I think it is very simply a patent that will let Canon make an adapter IF they ever decide to make a FF mirrorless camera. The adapter will allow folks to use their current EF lenses on the mirrorless camera at full frame and their EF-S lenses at the usual crop size. The camera as well as the adapter will be able to switch from one size to the other. No changes to the focal distance or anything else.


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## Mt Spokane Photography (Jun 26, 2015)

pedroesteban said:


> . It wouldn't surprise me if Canon developed a satisfactory EVF and decided that the upcoming 1dx mk II, 5d mkIV or 6d mk II will be mirrorless. I'd bet on a mirrorless 6d mk II.



Canon buys EVF's from Sony, their rear LCD's come from Sony as well, at least the one's I've removed say Sony on them. Canon does Not develop or make EVF's.

although companies in Japan are competitors, they are also business partners and buy pieces and parts from each other. Its a lot different than what we have in Western Companies.

As for a lens mount, perhaps some remember the new lens mount for FF that was in the patent news a few months ago. Canon has already said that the "M" mount is not suitable for FF.


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## optikus (Jun 27, 2015)

Hello,

what I expect to be seen in the near future is a new type of FF-mirrorless camera from Canon, and the patent shown here is for me a fitting element of this to grant continuity with the EF and EF-S-Lineup. Sony has shown that it can make sense to have a crop-mode in combination with high-megapixel-sensors, 5Ds has too. Therefore the compatibility of a VF-mirrorless perhaps as a competitor for A7II necessarily has to handle also APS-C-lenses if Canon will avoid an affront to the APS-C-Users they have. The patent shown seems to contain what Sony-Users know well, adaptor to other company-used standards. A E/EOS-Adapter from Sony is hard to imagine, a cooperation to manufacturers of those adapters is possible, as heard the A7II shall work together with EF-lenses nearly or identical as good as a EOS-body ... It's the proof for me that it is possible when it shall pe possible!


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## Mt Spokane Photography (Jun 30, 2015)

dilbert said:


> Mt Spokane Photography said:
> 
> 
> > ...
> ...



I suppose you are counting mounts for camcorders too  

For Canon SLR/DSLR's, I am aware of three mounts. All Canon SLR bodies had one of the three mounts, DSLR bodies have had only one mount. (Lenses have EF and EF-s, but all the bodies have a EF mount)

Canon started with a version of a Leica R mount for their first DSLR. They then went to the successful FL / FD breach lock mount, and then the EF (Electric Focus) mount which is used on all DSLR's since.

The EOS M is not a DSLR, but has its own mount. EF-s lenses mount to a EF mount but not on FF DSLR's. You can buy some Canon cinema cameras with the cinema industry standard PL mount, but its not a Canon mount.

I can still use the first EF lens made on any current canon DSLR. I believe that only Canon is able to use their first autofocus lens mount with complete compatibility on current models. Nikon can't., Sony/Minolta can't. The reason is that the other camera makers used a screw drive before going to a electronic focus system, so they had to redo their lens mounts to add more contacts. I think you will find multiple versions of their mounts.

I can't begin to count the dozen or so versions of mounts that Pentax used.

Now, with the many mirrorless cameras in circulation, its getting pretty crazy. Buyers run the risk of having lenses that only fit discontinued cameras. This is a reality, because, some manufacturers and or models will drop out.


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## johnctharp (Jul 1, 2015)

I think that the only reason for this patent to exist is that the current EF -> EF-M adapter 'crops' EF lenses to an APS-C image circle.

The EF-M mount, same as Sony's E-mount, has room for a full-frame sensor, and with the proper adapter would allow full usage of EF lenses.


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