A hypothesis concerning the RF mount

[clicstudio]

Messing up 3rd party lens compatibility would be a bummer, but will guarantee more Canon lens sales.

Makes sense. A "convertible" camera... Why not? The camera recognizes the lens attached to it already so it should be a transparent solution. Use your old EF or the New EF-R or R or whatever they will call it without any special adapters. Awesome!

 

[ahsanford]

I don't understand the point of mounting an EF lens directly onto the mirrorless camera body. It will be much too close to the sensor. How could it possibly work?

You presume it will be thin. That may be a bad presumption.

This could be a full EF mount visually, form-wise, etc, but possibly provide other functionality for newer lenses.

- A

 

[amorse]

I don't see how it's a new mount. If new lenses and new bodies are both backward-compatible (there is no reason for them not to be), just call it "EF mount".

I'm guessing here, but maybe it could need to be referred to as a new mount while being backwards compatible because the RF lenses will not be compatible with DSLRs. I.e. and EF lens will mount to an EF or RF mount, but an RF lens will only mount to an RF mount.

 

[Richard-CN]

Things seem to be getting pretty whacky around here.

Craig: are the current sources trusted? I don't see any CR# ratings... does this mean that we're all falling for internet gossip and wishful thinking. What if Canon Rumors' original position turns out to be correct all along?

I don't know, but it's just not feeling like we are less than a week from what would be Canon's biggest product announcement for a generation and indicate the future of the EF mount. Canon are pretty good at playing their cards close to their chest, but it has never been this quiet before...

Well, this post was done by me, not Craig, but Craig wanted it up today to see what the community thought of the concept after him and I discussed it today. it's backed up by patent applications and one of his sources saying EF mount lenses mount on it and others saying it has a new "RF mount".

It's also why there was a pretty big caveat mentioned in the bottom of the post. No one knows much of anything at this point

 

[ahsanford]

Can someone give me the short version of these patents?

Is it identical form-wise (flange distance, physical mount ring, etc.) to EF but it just provides extra communications and options for interacting with the lens?

Or is it a nested lens mount concept with two different flange distances?

- A

 

[clicstudio]

Or the M-series!

The Sony 24-70 for My A7R III is HUGE, a lot longer and heavier than the Canon.
In a skinny body it makes the camera harder to balance. Even with the vertical grip attached.
I hope canon gives us a DSLR-body without a mirror and a convertible mount.

 

[3kramd5]

For the Sensor to more back and forth waht 12mm? would there be an extra 12mm of space lost to accommodate old lenses?
How could you get the mechanical sensor moving reliably for say 10,000 movements?

Here are two possible ways:
1) sensor based alignment (sensor picks up three targets on the lens mount to locate and align;
2) kinematic Mount (moving “platform” engages to a set of 1-DOR, 2-DOR, and 3-DOR hard stops at the end of each translation (mating stops on both sides of platform) for repeatable deployments.

Both could be expensive, but I expect an actuated sensor with the ability to locate and align itself to a lens mount both be both simpler and better.

 

[ahsanford]

I'd been wondering a while back if they'd use the same mount but create mirrorless lenses which can extend further back internally, behind the mount. With no mirror in the way perhaps they can support EF lenses and potentially more compact overall mirrorless oriented lenses that way.

You'd need some really bizarre rear lens caps for RF lenses if that's how they're designed, but so be it.

Read this. The forum already beat this up here. Verdict = possible, but complicated.

- A

 

[clicstudio]

Considering that the 5D series is a little too thin for my hands, I certainly wouldn't be interested in a thinner body than that.

the Sony A7R III is skinny as hell. Taking off the mirror doesn't mean they have to make the camera smaller or thinner. They can release a consumer version and a big,, thick Pro version for the big white lenses.

 

[Richard-CN]

Can someone give me the short version of these patents?

Is it identical form-wise (flange distance, physical mount ring, etc.) to EF but it just provides extra communications and options for interacting with the lens?

Or is it a nested lens mount concept with two different flange distances?

- A

essentially the patent discuss mounting lenses that have different protocols on a mount that can service both protocols.

Ie: EF lens protocols and RF lens protocols.

the communicate modes which the interchangeable lens can respond may differ. In order to be able to equip an imaging device with the interchangeable lens of several different types, the technology which distinguishes the type of interchangeable lens with which it was equipped is disclosed.

or this...

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.

It's awkward but sums it up. They don't talk that clearly about the registration distance. THAT fact we gathered from other sources that stated EF lenses were mounting on the camera as if they were RF lenses. The patent simply describe a method of using one mount supporting two different types of lenses, which is exactly what we are surmising here.

Essentially RF lenses will be faster and probably tuned more for mirrorless. EF lenses will mount and work as if they are native to the mount as well.

It's unknown if canon would make DSLR's that could mount an RF mount lens, or whether there will be something similar to the EF-S lenses that prevents the mount from occuring.

 

[ahsanford]

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.

Yes. This.



Head here to read the team's take on it.

- A

 

[clicstudio]

Here are two possible ways:
1) sensor based alignment (sensor picks up three targets on the lens mount to locate and align;
2) kinematic Mount (moving “platform” engages to a set of 1-DOR, 2-DOR, and 3-DOR hard stops at the end of each translation (mating stops on both sides of platform) for repeatable deployments.

Both could be expensive, but I expect an actuated sensor with the ability to locate and align itself to a lens mount both be both simpler and better.

sounds interesting too but I wonder if the mechanism would last thousands of actuations and not shift over time. Anything movable has a chance to become misaligned

 

[amorse]

Well, this post was done by me, not Craig, but Craig wanted it up today to see what the community thought of the concept after him and I discussed it today. it's backed up by patent applications and one of his sources saying EF mount lenses mount on it and others saying it has a new "RF mount".

It's also why there was a pretty big caveat mentioned in the bottom of the post. No one knows much of anything at this point

Yes, I think an earlier post noted that there will be no CR ratings on these posts moving forward because sources were somewhat unknown, but there was reason to start thinking there could be merit to some of the suggestions.

To be fair though, there is so much interest in this and no information to go on, so the choice is really report on nothing at all or report on less reliable rumours while being clear that their likelihood of accuracy is not verified. I prefer to hear the unverified rumours (obviously caveated) to hearing nothing at all.

Big grains of salt all around, but let the frothing at the mouth continue!

 

[3kramd5]

sounds interesting too but I wonder if the mechanism would last thousands of actuations and not shift over time. Anything movable has a chance to become misaligned

Which is why (1) is what I present as better. The idea is that the sensor measures its location and orientation relative to the mounting flange of the lens, and commands the actuators until it’s within spec.

(2) would be limited by the robustness of the hardstops. Kinematic mounts work and work well, but they would be subject to wear which would affect alignment.

But I expect neither (1) nor (2)

 

[Richard-CN]

Yes, I think an earlier post noted that there will be no CR ratings on these posts moving forward because sources were somewhat unknown, but there was reason to start thinking there could be merit to some of the suggestions.

To be fair though, there is so much interest in this and no information to go on, so the choice is really report on nothing at all or report on less reliable rumours while being clear that their likelihood of accuracy is not verified. I prefer to hear the unverified rumours (obviously caveated) to hearing nothing at all.

Big grains of salt all around, but let the frothing at the mouth continue!

Of course. With canon keeping this SO quiet it's just hypothetical musings right now, but we did back it up with some form of logic

I also tend to do the crazy posts when Craig allows me to

It's crazy how quiet this is, usually full specs are known and we usually have the first images by now.

 

[drob]

So is it safe to say that EOS M was never intended to be developed into a full frame, pro-level system?

 

[Kit.]

Can someone give me the short version of these patents?

Something akin to (from the body - SPI master - point of view):
1. Detect that a lens is connected.
2. Start communicating on a default SPI clock rate (supported by all EF lenses).
3. If the lens reports that it supports a higher SPI clock rate, use a higher SPI clock rate.

Really nothing that would warrant changing the mount name.

 

[nchoh]

For this reason (reliability), I believe the sensor will be fixed at the standard EF flange distance and new EF-R lenses will simply extend into the body and sit much closer to the sensor. Very simple, reliable and the best of both worlds in terms of short flange distance and full native EF support.

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.

Most likely an interim solution. After, say 5 years, when a fuller stable of EF-R lenses are released, a slim, EF-R only camera will be released?

 

[amorse]

How about an even crazier hypothesis - what if Canon is introducing a curved sensor? Canon has several patent applications for curved sensors and I believe one of which could change its curve electronically. With that kind of technology (if I'm understanding it correctly, which I may not be), Canon could open the door to very different lens designs, possibly justifying a new mount.

 

[Ditboy]

Continue reading...

If the theories about keeping the current flange distance for EF lens compatibility and the new R lenses using protruding elements into the mirror space to optimize optical formulas is true, hats off to the designers of the EF mount for their forward thinking. That would also make the R lenses the third mount to utilize the same basic design. It would be a "very sexy" solution.