Patent: Improved EF to EF-M Adaptor

[Canon Rumors]

A new patent for an EF to EF-M adaptor has appeared. It looks like the new adaptor will have improved AF speed with EF lenses mounted. As many of you know, the current adaptor is pretty sluggish in that regard.</p>
<p>The patent makes a point of saying there will be improved performance for video and liveview. Could the video improvement be for dual pixel AF? Could this patent be related to the <a href="http://www.canonrumors.com/2015/02/whats-next-from-canon-nab-and-beyond/" target="_blank">GH4 competitor we’ve been told would launch at NAB</a>?</p>
<p>The patent details are after the break….</p>
<p><!--more--></p>
<p><strong>Patent Publication No. 2015-34903</strong></p>
<ul>
<li>Published 2015.2.19</li>
<li>Filing date 2013.8.9</li>
</ul>
<p><strong>Master lens</strong></p>
<ul>
<li>Zoom ratio 2.69</li>
<li>Focal length 72.13 135.02 193.99mm</li>
<li>Fno. 2.90</li>
<li>Half angle ω = 10.72 5.78 4.03 °</li>
<li>Image height Y = 13.66mm</li>
<li>Overall length of the lens 237.36mm</li>
<li>BF 54.00mm</li>
</ul>
<p><strong>Adapter installed</strong></p>
<ul>
<li>Zoom ratio 2.69</li>
<li>The focal length f = 72.12 135.00 193.96mm</li>
<li>Fno. 2.90</li>
<li>Half angle ω = 10.72 5.78 4.03 °</li>
<li>Image height Y = 13.66mm</li>
<li>Overall length of the lens 239.70mm</li>
<li>BF 16.77mm</li>
</ul>
<p><strong>Canon patent</strong></p>
<ul>
<li>Fast AF adapter</li>
<li>Wobbling corresponding</li>
<li>3-group configuration of positive and negative positive</li>
<li>2 group also serves as a focus group and the anti-vibration group</li>
<li>And realize high-speed AF focus group was lighter</li>
</ul>
<p>Source: [<a href="http://egami.blog.so-net.ne.jp/2015-02-23" target="_blank">Egami</a>]</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>

 

[iron-t]

This thing is going to cost a fortune, looks like it contains its own focusing group! This seems like a very complicated way to go about solving AF speed problems--possibly even more complicated than Sony's mirrorless-to-SLR-lens adapters with pellicle mirrors and full phase-detect systems on board. Which is no doubt covered by a raft of Sony patents.

I have no idea how useful this Canon concept is. My impression has always been that the limiting factor in focusing speed for EF lenses mounted on M bodies was the very slow overall speed of the AF system in the body. That being said, some lenses do far better than others. My EF 50mm f/1.4 and Tamron SP 24-70mm VC are all but useless on EOS M, whereas my 100L and 70-200L are more or less usable (ignoring the absurd ergonomics).

 

[bf]

Any news on ef-m development is welcome although I'd rather to see more innovation on the native lenses rather than the adapters.

 

[lol]

"Wobbling corresponding"
"2 group also serves as a focus group and the anti-vibration group"

Not sure how to read that, but one way might be it can also provide IS to non-IS lenses???

 

[-1]

Looks like a custom adapter for a specific ”master lens”...

 

[NorbR]

Weird solution if the goal is only to improve focus speed. On the other hand, since this has optics inside, it could also work as some sort of speed booster / focal reducer for the M mount ...

 

[lw]

To be clear, it isn't a patent for an "EF to EF-M adaptor", as the patent makes no references to any particular Canon product line. Rather it applies to "interchangeable lens devices" when using contrast-based AF (and is not specific about mirrorless).

In fact the patent primarily uses the term "D-SLR" to describe the camera the adaptor is used with. (but that's just an example I think - the patent isn't specific to DSLR)

 

[mb66energy]

The master lens is called EF-M 70-200 f/2.8 IS in the patent (strange?!) ...

The lens adapter might istself work as
(1) an IS unit
(2) AF aid by wobbeling one lens element:

Ad (2): My idea is about the correlated action of a lens moving forth and back with e.g. 30 Hz and
a contrast detection on the sensor. The cameras processor can decide which lens position
gives a better contrast detect and knows the direction where to focus the main lens
based on the wobbeling lens element position and the sensor contrast detect signal.

If the main lens has achieved right focusing the wobbeling is stopped. An ingenious idea that might be
as effective as phase detect and accurate like contrast detect.

But I am confused by the EF-M 70-200 ...

 

[Mt Spokane Photography]

The Adaptor contains moving elements to assist in contrast detection focusing. The elements are light weight and can move very rapidly to detect the correct focus. In a large lens, this is not practical, but in the adapter it is. Then, the command goes to the main lens that moves the focus assembly to the correct position.

"According to the present invention, the image side of an imaging optical system (main lens system) is equipped removably, and the attachment lens which can detect the focusing state of the whole system at high speed and with high precision is obtained. "


This makes contrast detect AF happen more quickly. Wobbling as in the translation refers to moving a lens back and forth to determine the sharpest focus This is done when using contrast detect AF.

Here is the portion of the operation that describes how it improves focus speed.

"In focusing operation, a focusing glass group is vibrated to an optical axis direction at high speed, and the gap direction from a focusing state (henceforth "wobbling") is detected. The optimal position of the focusing glass group used as a focusing state is computed by detecting the signal component of the specific frequency band of an imaging range from the output signal of imaging sensors after wobbling.
[0005]
Then, a focusing glass group is moved to an optimal position, and it becomes the completion of a focus."

The patent is not specific to a "M" camera, it can be usued on DSLR's, Surveillance cameras, etc. However, the M is a obvious candidate.

Patents like this were started thru the system 1-1'/2 years prior, and were the result of research as much as 4 or 5 years before that.

With Dual Pixel Technology, the invention is not needed, so its likely just to protect the investment in research and to be a solution if the need arises. It does raise the question about dual pixel use in a future mirrorless body.

 

[lw]

The master lens is called EF-M 70-200 f/2.8 IS in the patent (strange?!) ...

But I am confused by the EF-M 70-200 ...

The patent makes no such reference. Egami's blog does.
The lens isn't named in the patent filing.
Egami refers to is as EF-M 70-200 in one place, and just as 70-200 elsewhere.

I wouldn't take machine translations as gospel

 

[mb66energy]

The master lens is called EF-M 70-200 f/2.8 IS in the patent (strange?!) ...

But I am confused by the EF-M 70-200 ...

The patent makes no such reference. Egami's blog does.
The lens isn't named in the patent filing.
Egami refers to is as EF-M 70-200 in one place, and just as 70-200 elsewhere.

I wouldn't take machine translations as gospel

Thanks lw ! - You saved from a sleepless night! - Best, Michael

 

[Mt Spokane Photography]

I could see this patent used in a TC. AF gets slow at times using a TC, and this could speed it up. The EOS to M adapter is basically a TC with a very slight magnification, which has different interfaces on each end. The slight magnification eliminates some of the vignetting caused by the adapter.

 

[Ebrahim Saadawi]

The EOS to M adapter is basically a TC with a very slight magnification, which has different interfaces on each end. The slight magnification eliminates some of the vignetting caused by the adapter.

Just to correct the current EF to EF-M adapter has no any optical elements, just hollow air. It's just a flange-distance corrector with electronics, no magnifying or reduction. Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

 

[privatebydesign]

Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

No it wouldn't, it would give you lens equivalence but it would do nothing for COC and noise, characteristics inherent in a sensors size.

 

[Ebrahim Saadawi]

Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

No it wouldn't, it would give you lens equivalence but it would do nothing for COC and noise, characteristics inherent in a sensors size.

Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

No it wouldn't, it would give you lens equivalence but it would do nothing for COC and noise, characteristics inherent in a sensors size.

Yes it would. Effectively.

the Sb elements do not increase the physical sensor size, obviously.

Sensor performance (DR-Resolution-tonal range etc) of the Eos m APS-C sensors (24 and 18mp) is similar to Canon's own 5D/6D performance. And it also increases lowlight performance by a full stop. Yes it would not construct a larger sensor area (obviously) but it effectively turns it into FF. When using a Canon EF lens, it would give the exact same image aesthetic as on a 5D, (as in same field of view, same shallow depth of field, 24mp, same DR, maybe slightly worse noise performance if the 5D/6D has more than 1 full stop advantage). It really does work, using a SB+FF lens with an a6000 gives an almost 99% identical image to using same lens on a FF A7. Just try an aps-c with a SB, it's FF, really work! If there are major differences between the two sensor inherent performance of course that will show up.

This simple product can really make the cheapest FF solution out there and give the low-end market access to the FF aesthetic with a 200$ eos-m and 100$ 50mm 1.8 II. I am sure it will come up soon if not from Canon then from all those third party focal-reducer makers, when the eos-m is popular enough.

 

[Coldhands]

Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

No it wouldn't, it would give you lens equivalence but it would do nothing for COC and noise, characteristics inherent in a sensors size.

Yes it would. Effectively.

the Sb elements do not increase the physical sensor size, obviously.

Sensor performance (DR-Resolution-tonal range etc) of the Eos m APS-C sensors (24 and 18mp) is similar to Canon's own 5D/6D performance. And it also increases lowlight performance by a full stop. Yes it would not construct a larger sensor area (obviously) but it effectively turns it into FF. When using a Canon EF lens, it would give the exact same image aesthetic as on a 5D, (as in same field of view, same shallow depth of field, 24mp, same DR, maybe slightly worse noise performance if the 5D/6D has more than 1 full stop advantage). It really does work, using a SB+FF lens with an a6000 gives an almost 99% identical image to using same lens on a FF A7. Just try an aps-c with a SB, it's FF, really work! If there are major differences between the two sensor inherent performance of course that will show up.

This simple product can really make the cheapest FF solution out there and give the low-end market access to the FF aesthetic with a 200$ eos-m and 100$ 50mm 1.8 II. I am sure it will come up soon if not from Canon then from all those third party focal-reducer makers, when the eos-m is popular enough.

The speed-booster is a novel concept and certainly has its uses, but it is far from the panacea you're trying to present it as.

A) It gives a FoV and DoF approximately equal to a full frame lens on a native camera, not exactly. The image angle is still slightly narrower and the effective aperture slightly smaller.

B) The noise equivalence only holds true if the the comparable FF sensor has in ISO advantage of less than or equal to one stop over APS-C (the amount of light added by concentrating the FF area onto APS-C), as you yourself have already pointed out.

C) The resolution achieved by FF lens + SB on APS-C is nowhere near the resolution of the lens on a native FF camera. Although centre sharpness is similar when the lens is stopped down, corner sharpness suffers, as well as overall sharpness at larger apertures. Also chromatic aberrations are much more severe.

D) The dynamic range will not match a FF sensor as the smaller pixels have a smaller electron well. Throwing more photons at them won't help anything.

Even setting aside all if these points, it only takes a few moments of logical reasoning to conclude that if a speed-booster really was a "silver bullet" that gave all the benefits of FF without the actual sensor size, then we would all be using cameras with tiny sensors and optics with this effect built-in. The fact the we don't is testament to the fact that this method has drawbacks that are significant enough to relegate it to a niche product.

 

[Mt Spokane Photography]

The EOS to M adapter is basically a TC with a very slight magnification, which has different interfaces on each end. The slight magnification eliminates some of the vignetting caused by the adapter.

Just to correct the current EF to EF-M adapter has no any optical elements, just hollow air. It's just a flange-distance corrector with electronics, no magnifying or reduction. Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

We are talking about the patent for a new EOS-M adapter. Did you miss that? It does have lens elements in it!

 

[BL]

I'm calling it. Asia and ROW only. Not available in the US :

 

[Ebrahim Saadawi]

Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

No it wouldn't, it would give you lens equivalence but it would do nothing for COC and noise, characteristics inherent in a sensors size.

Yes it would. Effectively.

the Sb elements do not increase the physical sensor size, obviously.

Sensor performance (DR-Resolution-tonal range etc) of the Eos m APS-C sensors (24 and 18mp) is similar to Canon's own 5D/6D performance. And it also increases lowlight performance by a full stop. Yes it would not construct a larger sensor area (obviously) but it effectively turns it into FF. When using a Canon EF lens, it would give the exact same image aesthetic as on a 5D, (as in same field of view, same shallow depth of field, 24mp, same DR, maybe slightly worse noise performance if the 5D/6D has more than 1 full stop advantage). It really does work, using a SB+FF lens with an a6000 gives an almost 99% identical image to using same lens on a FF A7. Just try an aps-c with a SB, it's FF, really work! If there are major differences between the two sensor inherent performance of course that will show up.

This simple product can really make the cheapest FF solution out there and give the low-end market access to the FF aesthetic with a 200$ eos-m and 100$ 50mm 1.8 II. I am sure it will come up soon if not from Canon then from all those third party focal-reducer makers, when the eos-m is popular enough.

The speed-booster is a novel concept and certainly has its uses, but it is far from the panacea you're trying to present it as.

A) It gives a FoV and DoF approximately equal to a full frame lens on a native camera, not exactly. The image angle is still slightly narrower and the effective aperture slightly smaller.

B) The noise equivalence only holds true if the the comparable FF sensor has in ISO advantage of less than or equal to one stop over APS-C (the amount of light added by concentrating the FF area onto APS-C), as you yourself have already pointed out.

C) The resolution achieved by FF lens + SB on APS-C is nowhere near the resolution of the lens on a native FF camera. Although centre sharpness is similar when the lens is stopped down, corner sharpness suffers, as well as overall sharpness at larger apertures. Also chromatic aberrations are much more severe.

D) The dynamic range will not match a FF sensor as the smaller pixels have a smaller electron well. Throwing more photons at them won't help anything.

Even setting aside all if these points, it only takes a few moments of logical reasoning to conclude that if a speed-booster really was a "silver bullet" that gave all the benefits of FF without the actual sensor size, then we would all be using cameras with tiny sensors and optics with this effect built-in. The fact the we don't is testament to the fact that this method has drawbacks that are significant enough to relegate it to a niche product.

It really us the silver bullet. Just try it. I am shooting 99% A7 quality with an APS-C A6000, it's magical. In fact, the a6000 was a much inferior camera than before I used the SB and effectively turned it into FF. It's exactly the same field of view, the same DOF, and the same aesthetic people love about FF. The fact why we're not all using tiny sensors and SB-like elements is because you still need a large FF lens, and on the engineering side of sensors a very small one cant be made to match a FF one, but with the APS-C vs FF, they're freakishly close. In fact, many APS-C sensors out perform FF ones in many ways and vice versa, for example a D5300 vs 5D mk III, but the 5D givea better images (even though it has
ower DR and resolution) because it has that FF aesthetic.

I have no benefit from marketing focal reducers, I am just someone who used them and saw they gave me a FF sensor with no drawbacks (the well made ones), in fact they even improve lens sharpness a bit and improve the NTF charts performance, so I thought I'd share an idea on the EOS M adapter. I do believe that making such an adapter would be a very good approach even compared to making more expensive FF versions of the EOS M, I saw that with the A6000 + SB vs FF A7. I think if Canon made an EOS-M + SB adapter virtually all users would be stunned by the FF images compared to a normal adapter and that most people would'nt be able to tell 5D vs eos M + SB apart, as I ser with the A6000 vs A7 here.

It's a magical invention and effectively turns an APS-C to a FF. The only downside is AF and lens communication issues that's why it'd be almost perfect if Canon themselves did it instead of Metabones.

 

[Ebrahim Saadawi]

The EOS to M adapter is basically a TC with a very slight magnification, which has different interfaces on each end. The slight magnification eliminates some of the vignetting caused by the adapter.

Just to correct the current EF to EF-M adapter has no any optical elements, just hollow air. It's just a flange-distance corrector with electronics, no magnifying or reduction. Fun fact: If you put Speedbooster optics (focal reducing) in the eos-m adapter, it would turn the EOS-M cameras into a Fullframe mirrorless for 200$ new body.

We are talking about the patent for a new EOS-M adapter. Did you miss that? It does have lens elements in it!

Yes I missed that and though you were talking of the current EOS M since you're saying ''the'' eos to m adapter ''is'' a TC.

Sorry if I misunderstood. So does this new one has a TC effect and reduces viggentting in the patent? I would'nt like that.