# Patent: New Canon Mount Coming?



## Canon Rumors Guy (Jun 1, 2018)

```
A patent for serial communication for an ILC mount that is neither EF or EF-M.</p>
<p><a href="https://www.canonnews.com/canon-patent-application-the-first-sniff-of-a-new-mount-for-canon">Canon News</a> tried their best to translate a rather awkward patent.</p>
<blockquote><p>…… is seemingly suggesting that this mount could handle multiple lenses of both a new mount and old mount format.  Conjecturing by looking at the mount, looking at the size of the sensor against the mount itself, it’s appearing as if canon is looking at mounting EF-M and EF Full frame mirrorless using possibly a hybrid mount?</p></blockquote>
<p><strong>From Japan Patent Application 2018-084713:</strong></p>
<blockquote><p>Conventionally, the serial communication (synchronous serial communication) of a clock synchronization system has been adopted as a communication method of a camera and an interchangeable lens. The following technical contents are disclosed in the Patent document 1. First, synchronous serial communication is performed with the first communication speed with which an interchangeable lens old type can also communicate. When the interchangeable lens with which it is equipped is distinguished from a new lens by the communication content, it changes to the synchronous serial communication in a more nearly high-speed second communication speed.</p></blockquote>
<p>We’ve been told that the mount solution for a full frame mirrorless camera would be interesting, but this is the first time we can confirm that Canon is working on a new mount. Though there’s no way of knowing if this is indeed for the upcoming full frame mirrorless camera body.</p>
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## Talys (Jun 1, 2018)

A camera body that could accept efm recessed and ef protruded would be pretty amazing


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## Don Haines (Jun 1, 2018)

Actually.......

The patent is about communication protocols between the lens and the body..... I did this around 1990 with high speed modems.....

The current lenses communicate to the lenses in an asynchronous protocol.... there are stop bits, start bits, parity bits, and as a result, asynchronous communications are fairly slow and add latency to the communications pipeline.... as a result, there is delay between when the camera issues a command and the lens receives it.

What this does is to establish initial communications with all lenses in async mode, queries the lens as to what speeds and protocols it supports, and then goes to the highest supported speed/ protocol. If it is an old lens, the camera gets an error or an “unrecognized command” response from the lens and stays at the old speed that all the current lenses are using. If it is a new lens that supports this command, communications change to sync mode and a higher bit rate. Now commands are transmitted faster and there is less delay.... allowing faster focus speeds and better IS performance.

All your legacy lenses still work, and the new ones are even better! Who knows, the two 70-200 lenses about to be released could be the first to hit the shelves.....


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## canonnews (Jun 1, 2018)

Don Haines said:


> Actually.......
> 
> The patent is about communication protocols between the lens and the body..... I did this around 1990 with high speed modems..



Yes. We mentioned that, however that's not the interesting part we were surprised about. The mount shown is neither the EF nor the EF-M mount, but another derivative. the sensor portion looks larger than what it would be for an EF mount, and closer to a full frame sensor in an EF-M mount.

So it would be high speed Async EF or EF-M sized mount that could handle legacy lenses. The idea place to split this is with mirrorless system that probably requires faster and more immediate adjustments than the DSLR EF mount.


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## HarryFilm (Jun 1, 2018)

I'm almost, but not, maybe YES...going to say...I TOLD YOU SO !!!

Based upon some lava-hot rumors not only are we seeing new mounts but the cameras that will GO WITH THOSE MOUNT!

My current Euro-engineering sources have been saying for a Looooooong time that a Canon Medium Format with a much-larger-than-EF-mount is being tested, and large smartphone(s) with 2/3rds inch and/or APS-C sensors are on the way, and a medium-duty global shutter mirrorless combo cinema/stills camera is on the way (XC-15 style). If this mount is Full Frame then it would LIKELY be put on an M5-style body for the Sony A7sII-like small form factor video-centric crowd!


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## Orangutan (Jun 1, 2018)

HarryFilm said:


> I'm almost, but not



NOT until the product is actually released.


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## -1 (Jun 1, 2018)

Don Haines said:


> The patent is about communication protocols between the lens and the body..... I did this around 1990 with high speed modems.....
> [---]
> All your legacy lenses still work, and the new ones are even better! Who knows, the two 70-200 lenses about to be released could be the first to hit the shelves.....



So it's physically a dummy. That would be a good explanation to why it looks like EF-M mount twisted a few degrees anticlockwise. That that's seem to be expected then is a EF-M mount with a new protocol and that an adapter is to be used for EF lenses... Could be one like these with a Pelix mirror to assist a phase AF system:


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## OlAf (Jun 1, 2018)

It would be nice to do without adapters-crutches.


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## fullstop (Jun 1, 2018)

patent is only about communications.

mount-parameters are just dummy specs. purported ability to mount EF-M lenses (crop image circle) on upcoming FF- sensored mirrorless cameras makes no sense! and if canon were to use EF-M mount for FF mirrorless, then the simple extension-tube with wiring-thru EF/EF-M adapter is already available. 

i agree with user -1 that it MIGHT hint towards a "Sony LA-EA4 type" of adapter (possibly with pellicle mirror) to retain legacy EF lenses phase-AF properties on FF mirrorless system.


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## Kit. (Jun 1, 2018)

canonnews said:


> Yes. We mentioned that, however that's not the interesting part we were surprised about. The mount shown is neither the EF nor the EF-M mount, but another derivative. the sensor portion looks larger than what it would be for an EF mount, and closer to a full frame sensor in an EF-M mount.
> 
> So it would be high speed Async EF or EF-M sized mount that could handle legacy lenses.


Or it could be just some abstract drawing as the patent is applicable to both EF and EF-M.

Or are there any specific patent claims related to mount details (other than the presence of serial interface contacts)?


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## jolyonralph (Jun 1, 2018)

I have to agree, this patent is just about communication protocols and has nothing to do with hardware changes at all.

The serial protocol used by lenses to communicate with the body dates back to 1986. Every EF lens made today still uses the same protocols so that they will work on a 1986 EOS 650 camera body.

Obviously modern technology allows MUCH faster communication (back in 1986 1200baud (bits per second) communication was the norm over a serial link, with some faster peripherals handling 9600bps. Now, with USB 3 serial we have 480 megabits per second - a 50,000 times increase in speed.)

So, the patent allows for a lens to communicate in such a way that a new lens and a new body can identify that they are both capable of high speed communication and then chatter away at a much faster rate (bringing down latency and therefore increasing focus speed and accuracy) - but in a way that allows both the lens and the body to fall back to the older protocols if a newer lens is attached to an older body, or vice versa. 

You need pictures on a patent otherwise they get a bit boring, but don't read too much into it.


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## keithcooper (Jun 1, 2018)

Whilst I'd like to see more mount detail, I suspect any new features that are different here are to make the the info applicable to any Canon mount, not a specific new one

Looking at the patent, I'm minded to agree that it's primarily about lens communication and perhaps should be seen in conjunction with this US application for a bit of (slightly) more readable exposition

http://pdfaiw.uspto.gov/.aiw?PageNum=0&docid=20180115697

This one looks at changing the number of data words communicated in messages. This matters because in rapid shooting and live-view, the existing data exchange protocols take too long. It also lets a lens communicate a large amount of data to a body quickly when first attached. An example of this would be custom lens aberration and calibration data, related to the actual lens you are using.

In terms of mount adapter, there was this one last month
http://pdfaiw.uspto.gov/.aiw?PageNum=0&docid=20180107098


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## mb66energy (Jun 1, 2018)

While the main content of the patent is about communication protocols the most interesting detail for me is
the ASPECT RATIO shown for the (possible) sensor (area). Maybe some preparation for larger than 36x24 mm sized sensors for future medium format sensors or multi-format large area to exploit the 43mm image circle of FF lenses in e.g. square format (31x31mm, very hypothetical I think).


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## eosuser1234 (Jun 1, 2018)

What if the ef adapter rotates out with the press of a lever. When an EF-M lens is used, it sits flush with the camera body, and blends in nicely. Will be intersting to see what size of image circle the new ef-m 32mm makes


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## fullstop (Jun 1, 2018)

eosuser1234 said:


> Will be interesting to see what size of image circle the new ef-m 32mm makes



just enough to cover Canon APS-C image circle - a bit more than r = 13.4 mm 

And again, I don't believe Canon will use EF-M mount for FF mirrorless. So no need to make a complicated EF-M adapter, since EF-M lenses and EF-M mount are *crop*. (no pun intended)


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## CafferyPhoto (Jun 1, 2018)

jolyonralph said:


> this patent is just about communication protocols


What protocols do the other companies (Sony, Nikon) use?


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## canonnews (Jun 1, 2018)

fullstop said:


> patent is only about communications.
> 
> mount-parameters are just dummy specs. purported ability to mount EF-M lenses (crop image circle) on upcoming FF- sensored mirrorless cameras makes no sense! and if canon were to use EF-M mount for FF mirrorless, then the simple extension-tube with wiring-thru EF/EF-M adapter is already available.



If it was just "dummy specs" then why not use existing diagrams that I'm sure Canon has in spades for the mechanical EF or EF-M mount, and why go through the additional time and effort to draft up a mount, and also the corresponding lens side of the mount. For no particular reason whatsoever. Why should a mount around the same diameter of an EF-M mount that clearly isn't an EF-M mount? Why show a lens with the same mount? It could very well be EF version 2.0 that is it portraying - one based upon asynchronous, faster communication between lens and mount, with different pin outs. Or it could be another all together.

while it's a patent dealing with the handshaking of an lens attached to a mount, it specifically mentions two different types of lenses being used on one mount.

secondly, every full frame camera manufacturer besides canon allows for crop lenses to attach and "auto crop" down to 1.5 or 1.6x in the case of Canon. Why would canon not offer the same functionality - how does that "not make sense". being able to use Canon's excellent 11-22mm in auto 1.6 crop sounds like a PERFECT great valid reason for me, or the 22/2 in auto crop as well.

and while a straight forward EF adapter already exists, it may not be as fast as Canon wants. they are obviously looking at faster lens communication for a reason.


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## ahsanford (Jun 1, 2018)

Again, it's just IP. Canon could have many R&D investments on the board that got to this stage (i.e. novel and non-obvious enough to be patented) that will never make it into a final product.

And, just for me, though it might be possible to have EF-X (new mount) or EF-M/EF-S tuck further into the mount than EF, has anyone actually superimposed the actual back of lenses for EF / EF-S / EF-M / this patent to see if that still physically might not be possible? In other words, have decisions already been made with the rear lens bayonet/locking features of EF that would (diametrically) block mirrorless rear elements from recessing inside of that EF mount?

- A


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## Mt Spokane Photography (Jun 1, 2018)

As I read the patent, its a protocol for greatly speeding up communication between camera and lens. It can potentially allow for a new lens design with higher speed communication, which has become a limiting factor for autofocus speed. It can be mounted to any camera because it is backwards compatible. New cameras will have a switch to detect the high speed lenses being mounted and increase voltage to the lens which switches on the high speed protocol.

"The object of this invention is providing the camera and interchangeable lens which enable improvement in the further performance of operation, corresponding also to the interchangeable lens old type which used the conventional communication method."

It can use the same number of contacts, so *its Potentially interchangeable. *As stated in this paragraph, when a lens with the high speed communication is mounted to a camera which does not support high speed, it defaults to the low speed.


"Although the conventional camera body can be equipped with the interchangeable lens 201 of this example, with the conventional camera body, the judgment according to lens type cannot be performed, but since it is corresponding only to the conventional system, the communication method as well as the conventional lens 301 operates, when the camera body side communicates a conventional system" 
"For this reason, it becomes possible to provide the camera and interchangeable lens which enable improvement in the further performance of operation, corresponding also to the interchangeable lens old type using the conventional communication method." 
"Since communication by suitable communicate mode can be started from immediately after wearing by judging promptly the kind of lens with which the camera was equipped, *without increasing the number of electrodes of a lens mount part* according to the present invention, It becomes possible to provide the camera and interchangeable lens which enable improvement in the further performance of operation, corresponding also to the interchangeable lens old type using the conventional communication method."


While it certainly could be used in a mirrorless lens for a mirrorless camera, they do not have a MIRROR Box.


"The mount lock pin 2 of Fig.1 is energized so that it may project from the attachment surface 1A of the camera body side mount 1 with a spring not shown, and it engages with the mount lock groove 6 of the lens side mount 5 of Fig.2 where it corresponds in a mount wearing completion state. T*he rectangular mirror box 4 is provided inside the camera body side mount 1, and the quick return mirror not shown, the shutter unit, the image sensor, etc. are arranged in the mirror box 4."*

There will be a switch added to the camera to be able to detect a lens with high speed protocol 

"If a camera body and a lens will be in a mount wearing completion state, in order to *depress the section of the judgment switch 105 classified by lens type on the camera body side *in addition to each electric contact being connected, The judgment switch 105 classified by lens type closes, and let the decision signal NEWLENS according to lens type by which pull-up is carried out to the power supply VDD for control be a "Lo" level. "


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## fullstop (Jun 1, 2018)

"auto crop" was introduced as a "stop gap fix" by Nikon when after years of preaching "DX is more than enough" they changed course in mid-stream and introduced FX bodies. So they a lot of customers sitting on DX lenses and wanted to tell them they can continue to use them on new FX cameras as well. Yes, technically they can. But no, in my opinion it still does not make sense in real life. It is a waste of precious sensor real estate and basically a "marketing trick". 

I never have and never will use lenses with too small an image circle for the sensor/imaging surface. If I dont have a proper lens and dont want to buy one outright, then I will RENT one. But "auto-crop"? Give me a break. 

YMMV


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## fullstop (Jun 1, 2018)

pressing "the judgement switch" sounds funny. Or frightening. Sound like the red button Trump and Korea Kim claim to have the bigger of.


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## jolyonralph (Jun 1, 2018)

Addressing a few points here.

1) The mount in the image has seven data pins. The EF mount has eight pins (the Extenders have a few more though and lenses that work with the extender have the pads to connect to these). The EF-M mount has nine pins.

So, the mount in the image is a mock-up of a generic mount. Nothing more.

2) These extra pins for the Extenders are probably what made Canon choose to avoid the simple solution of just adding a couple of new pins for the new communications channel.

3) For those who see no reason to use APS-C lenses on a FF body, that's your choice. There are many of us who would do this in certain cases. A 50mpx sensor for example gives an APS-C crop of a perfectly useable 20mpx, so if you're simply not able to buy all the FF lenses you want you can continue to use your regular EF-M lenses until you replace them.


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## takesome1 (Jun 1, 2018)

How about this idea:

It is not an M mount at all. It is a new mount they will use on new bodies, you will be able to use all of your existing lens.

Now the part where this makes Canon a ton of money, you buy a new lens it will only be compatible with the new bodies. If you want the latest new nifty lens you will have to shell out for the latest body.

It will make people mad and they will still buy the new lenses. Canon will make a ton of extra money off of it. Life goes on.


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## canonnews (Jun 1, 2018)

fullstop said:


> "auto crop" was introduced as a "stop gap fix" by Nikon



that's why both Sony and Nikon do it, and canon is the only one that does not.

just because you don't like it doesn't make it a valid use case.


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## canonnews (Jun 1, 2018)

jolyonralph said:


> Addressing a few points here.
> 
> 1) The mount in the image has seven data pins. The EF mount has eight pins (the Extenders have a few more though and lenses that work with the extender have the pads to connect to these). The EF-M mount has nine pins.
> 
> So, the mount in the image is a mock-up of a generic mount. Nothing more.



not really the communication between the mount and lens could need less pins than before. and they aren't all data pins. the EF mount has 3 ground pins. Two power and one Digital.

it entirely depends on how they interconnect, or even have a EF-X to EF adapter to support teleconvertor power,etc.

and even besides that, it's clear that canon is at least looking at EF 2.0 in this patent.


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## ahsanford (Jun 1, 2018)

fullstop said:


> "auto crop" was introduced as a "stop gap fix" by Nikon when after years of preaching "DX is more than enough" they changed course in mid-stream and introduced FX bodies. So they a lot of customers sitting on DX lenses and wanted to tell them they can continue to use them on new FX cameras as well. Yes, technically they can. But no, in my opinion it still does not make sense in real life. It is a waste of precious sensor real estate and basically a "marketing trick".



I agree in broad strokes with using all of the sensor you paid for, but what you call a marketing trick others might call a _far less steep cliff to climb to get into FF_. Some folks are financially constrained and need to wade through the upgrade process over time. 

Consider: Canon only sells two truly inexpensive EF lenses -- the 40 pancake and 50 f/1.8. If you had a 55-250, you're looking at a $1900 100-400L to replace that zoom range. If you use a standard zoom, Canon doesn't sell one in EF for less than $599. These things make the jump to FF a painful proposition.

...or if you are with Nikon you just keep snapping away with your DX glass until you can afford FX glass. By offering this, the full-frame cliff is a little less daunting. I don't see that as a negative -- not at all.

- A


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## ahsanford (Jun 1, 2018)

canonnews said:


> fullstop said:
> 
> 
> > "auto crop" was introduced as a "stop gap fix" by Nikon
> ...



+1. All day. 

And the genesis behind an idea should diminish the value of the idea. 

- A


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## fullstop (Jun 1, 2018)

all the Nikon shooters i know where quite excited at first and used their DX lenses a few times on FX bodies. But not for very long. All of them sold their DX lenses rather quickly and got "real glass" for FF sensors. 

Again, I'd rather rent an FF lens if I would not want to buy it, rather than using crop lenses on FF sensors.

There may well be a few people who see it differently, but from what i see in the real world, it is a small nich segment - definitely not a mainstream thing, that Canon should cater to in designing their new mirrorless FF camera system. But no problem here, if they - provided it does not get in my way and i don't have to subsidize it with purchase price.


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## 3kramd5 (Jun 2, 2018)

canonnews said:


> The idea place to split this is with mirrorless system that *probably requires faster and more immediate adjustments than the DSLR* EF mount.



Why is that probable?


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## Mt Spokane Photography (Jun 2, 2018)

The translation of this paragraph is pretty rough, but it tries to explain the need for a faster protocol. The camera must wait for the lens to respond (gets a busy signal), and that limits how fast a lens can operate. It did not refer to the need to pass more data, just a limit to exchanging information. I like the "evil" bit!

I think it may have the potential to become a new communication protocol for all lenses. It might be interesting to see if it appears in the new 70-200 lenses soon to be announced. Unless they announced it, someone would have to look for the bump or new hole that would match a future camera. It seems unlikely, but products have been introduced with hidden capabilities before.


"Calling Busy the state where this waiting time has arisen, a lens does not receive the communication from a camera between Bus(ies). Therefore, even if it raises the frequency of a clock, in order that the microcomputer on the camera side may communicate Busy release of a lens with waiting, there is a limit in improvement in performance of operation. Since the communication interrupt from a camera occurs frequently in the microcomputer on the lens side on the other hand, and communication interrupt processing for a Busy signal output and release must be performed preferentially each time, Since it becomes the evil of performance improvement of operation also here, the proposal which is not based on communication but judges a lens type exception is made."


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## HarryFilm (Jun 2, 2018)

CafferyPhoto said:


> jolyonralph said:
> 
> 
> > this patent is just about communication protocols
> ...




From an electrical point of view I am assuming a 2-bit, 3-bit or 4-bit parallel protocol much like the old-time Centronics printer ports but with less pins! In this case I suspect depending upon the number of pins on various mounts that Canon uses 2 data pin + 2 ground pins, or 3 data pins and 3 ground, or 4-pins for data and 4 pins for ground.

It could also be a serial protocol such as RS-232 or RS-422 like they used on old-style video cameras and editing decks. In terms of speed the Baud rate (in bits per second) Canon should be able to get between 56k/baud up to 384k/baud and depending upon the error correction protocol used which needs extra bits, it could be between 6000 bytes per second up to 48,000 bytes per second which is PLENTY to get and set various lens parameters at up to 120 frames per second! This means it would be CHEAP to produce (less than $3 per lens) because if they tried doing a micro-USB style serial communications system at MANY megabytes per second, it would cost between $10 to $150 extra per lens depending upon the lens parameters needed to be get/set and powered!


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## Mt Spokane Photography (Jun 2, 2018)

HarryFilm said:


> CafferyPhoto said:
> 
> 
> > jolyonralph said:
> ...


There is quite a bit of information about the existing lens protocol in the patent, it is described as a serial protocol. Since the communication protocol is from the 1980's, I suspect that its deadly slow. As to cost, its likely pennies per lens, it appears in even low end lenses like the 50mm 1.8 that costs about $10 to build.


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## Uneternal (Jun 3, 2018)

If this is the new mirrorless mount and it can take EF lenses, I was right and it will have a protruding element to change the flange distance for old EF lenses.

However the term "old type" from the patent could also just mean EF-M. So it probably takes these yet unknown "EF-X" and EF-M lenses?


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## mb66energy (Jun 3, 2018)

HarryFilm said:


> CafferyPhoto said:
> 
> 
> > jolyonralph said:
> ...



I think I have read that camera-lens-data exchange runs via I2C (maybe not Canon) and - I checked the following link:
https://photo.stackexchange.com/questions/61959/does-anyone-have-any-information-on-canons-vl-mount-regarding-pinout-and-protoc
Where the following contact scheme is provided:
Contact shape / Function
Dot / Battery voltage - supply for all actors
Bar shaped / Analog ground (minus) for actors like motors
------------------------------------------------------------------
Dot / Digital supply voltage
Dot / Digital data signal out from Camera to Lens
Dot / Digital data signal in from Lens to Camera
Dot / Digital clock signal to "align" the bits for both information channels
Dot / Digital ground (minus)

Which seems a well done arrangement for a mixed digital / analog system.

So it's definitely not RS-232/-485 (no common clock) nor I2C (only one data wire). If it is SPI (a synchronous serial interface using a common clock) they have no chip select (selection of a device) lines, maybe they use the cpu in the lens to interpret commands and send the info to the correct subdevices in the lens for e.g. focusing and electr(on)ic aperture.

Maybe Canon prepares to use I2C which needs one contact less. I2C is a wide spread communication protocol for sensors, displays and some actors. I2C uses address based bus devices (very flexible), allows more than one controler on the bus and can reach data transmission speeds up to 
>>>>>
– Standard-mode (Sm), with a bit rate up to 100 kbit/s [~10 kByte / s]
– Fast-mode (Fm), with a bit rate up to 400 kbit/s [~40 kByte / s]
– Fast-mode Plus (Fm+), with a bit rate up to 1 Mbit/s [~100 kByte / s]
– High-speed mode (Hs-mode), with a bit rate up to 3.4 Mbit/s. [~340 kByte / s]
<<<<<< from https://www.i2c-bus.org/specification/

A 100 Hz readout of an acceleration sensor wired up by I2C with an Arduino Nano and transfer to a Serial line via USB is no problem for me as a medium experienced former programmer - what if well experienced programmers use I2C and optimize it in a well designed environment?

And what for? Who knows but a lens using at least 3 linear drives (with 3 independent motors) for focusing could adjust lens group tilt by itself (via DPAF) or do some tilt to extend the content which is in focus. This would at least triple the amount of data for the focusing operation.


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## Kit. (Jun 4, 2018)

mb66energy said:


> If it is SPI (a synchronous serial interface using a common clock)


It's reportedly SPI running at ~80kHz clock sync. No need for slave select because back in the 80s no one expected to have more than 1 MCU in the lens.

Actually, I'm surprised that negotiation for higher speeds done at lower speed of the same serial protocol is patentable at all.


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## WoodyWindy (Jun 4, 2018)

mb66energy said:


> While the main content of the patent is about communication protocols the most interesting detail for me is
> the ASPECT RATIO shown for the (possible) sensor (area). Maybe some preparation for larger than 36x24 mm sized sensors for future medium format sensors or multi-format large area to exploit the 43mm image circle of FF lenses in e.g. square format (31x31mm, very hypothetical I think).



I was wondering if I was the only one who had noticed that. But, I agree with others pointing out that the primary purpose of this patent is the communication protocols (which, really, is questionably patentable material given serial communications' long history of protocol negotiation - but that's a whole 'nother story.) The imagery is probably just placeholder, and meant to convey the general concept of application


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## Kit. (Jun 4, 2018)

It's not a sensor, it's a mirror box. Which needs to be bigger than a sensor, especially in the vertical dimension.


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## dak723 (Jun 4, 2018)

WoodyWindy said:


> mb66energy said:
> 
> 
> > While the main content of the patent is about communication protocols the most interesting detail for me is
> ...



I agree that the image is very generic and with no dimensional information or scale bar it is meaningless.


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## fullstop (Jun 4, 2018)

Kit. said:


> It's not a sensor, it's a mirror box. Which needs to be bigger than a sensor, especially in the vertical dimension.



+1


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## Mt Spokane Photography (Jun 5, 2018)

Kit. said:


> mb66energy said:
> 
> 
> > If it is SPI (a synchronous serial interface using a common clock)
> ...


Its all about the manner in which the speed change is done without adding a additional contact as was required in the previous patent. Since the existing lenses must work with it, the method of detecting and switching is what sets it apart.


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## Kit. (Jun 5, 2018)

Mt Spokane Photography said:


> Kit. said:
> 
> 
> > Actually, I'm surprised that negotiation for higher speeds done at lower speed of the same serial protocol is patentable at all.
> ...


I just don't see how one could find a novel and non-obvious way of doing it in 2010s.

But probably the goal of Canon was not to provide a novel solution to speed negotiation "problem", but to keep its communication protocol patent-protected so that the 3rd party lens manufacturers would be unable to implement its coming extensions.


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## tmroper (Jun 5, 2018)

HarryFilm said:


> My current Euro-engineering sources have been saying for a Looooooong time that a Canon Medium Format with a much-larger-than-EF-mount is being tested,



I just realized that the patent drawing has a sensor with a 4:3 aspect ratio, which is a very common aspect ratio for medium format, and not common at all for smaller sensors. So there's that to add to the mystery as well.


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## fullstop (Jun 5, 2018)

tmroper said:


> I just realized that the patent drawing has a sensor with a 4:3 aspect ratio, which is a very common aspect ratio for medium format, and not common at all for smaller sensors. So there's that to add to the mystery as well.



it is the mirrorbox, not the sensor. We had that already earlier on in the thread.


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## Don Haines (Jun 5, 2018)

Kit. said:


> mb66energy said:
> 
> 
> > If it is SPI (a synchronous serial interface using a common clock)
> ...




It could be that the implementation is patented, not the concept.....


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## Mt Spokane Photography (Jun 6, 2018)

Don Haines said:


> Kit. said:
> 
> 
> > mb66energy said:
> ...


Concepts and Ideas cannot be patented. A working model that is complete enough to demonstrate the invention is required. 

This patent is based on previous patents, also owned by Canon. It differs in that a lens with the new protocol is able to be used with existing camera bodies, be they EF, EF-S, or M It could be used on a future mirrorless, but there is specific wording stating that the example is the preferred implementation, and that is a interchangeable lens camera.


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