# Patent: Some very strange full frame lenses



## Canon Rumors Guy (Aug 13, 2020)

> Canon News uncovered a patent showing some very strange optical formulas, they’re strange because of the back focus distance. The optical formulas in this patent have back focus distances of 0mm to 2mm.
> The EF mount has a back focus distance of around 44mm, while the RF mount is much closer at 18mm.
> I have a hard time believing Canon is going to get into the fixed-lens full-frame camera segment, but hey… I’d love that.
> *Canon 50mm f/1.2 *(Full Frame)
> ...



Continue reading...


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## H. Jones (Aug 13, 2020)

I'd pretend I would be a little mad as someone who just picked up the R5 and 35mm 1.8 as my everyday compact carry camera, but if Canon released a fixed lens full frame compact 35mm 1.4 camera I would probably still end up with one anyway for the fun of it


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## KeithBreazeal (Aug 13, 2020)

A BF of 0.00mm? Well, at least that would keep dust off the sensor!


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## bbasiaga (Aug 13, 2020)

No room for a mechanical shutter? 

Craziest application I can think of....canon ILC cell phone camera. 

-Brian


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## SV (Aug 13, 2020)

Can they be used on both RF and EF with special converters or adapters?


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## Canon Rumors Guy (Aug 13, 2020)

SV said:


> Can they be used on both RF and EF with special converters or adapters?



No, we're talking about flange distance, on EF, an adapter would hit the mirror, on RF the adapter would go inside the mount cavity.


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## TinTin (Aug 13, 2020)

18 mm? Isn't that EF-M? And RF is 20 mm.


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## Sharlin (Aug 13, 2020)

A reverse telescoping lens! Equipped with an inner barrel that extends out from the _rear_ of the lens, into the camera, when mounted. Technically possible with mirrorless!


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## Joules (Aug 13, 2020)

Sharlin said:


> A reverse telescoping lens! Equipped with an inner barrel that extends out from the _rear_ of the lens, into the camera, when mounted. Technically possible with mirrorless!


Possible. But it seems silly to make your lens extent less than 20 mm. Does that amount of space saving really matter to some people?


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## KeithBreazeal (Aug 13, 2020)

I think I know where Canon is heading with this. The electronic shutter has several issues, especially sports or panning. Canon may be on the way to a totally new method of reading the sensor. Currently, the sensor is read while it is still gathering photons. My thought is Canon might be designing a sensor where all the sensor's photodiodes are turned off at the desired shutter speed, then read. If this is where they are heading, there will be no need for the mechanical shutter, it will allow lens designs with minimal rear element to sensor distance. The closer the rear element is to the sensor, aberrations like Chromatic, Coma, and Spherical will be greatly reduced. If a lens has a minute amount of aberrations at the exit of the last element, the distance to the sensor is the key. Kind of like light going through a prism- the further away the prism is from the viewing surface, the wider the rainbow.(more noticeable Chromatic aberration) The final result is higher resolution and better contrast.


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## Deleted member 381342 (Aug 13, 2020)

You twist the lens and it comes out the camera a wee bit giving you a growing pancake lens.


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## Stuart (Aug 13, 2020)

Those lenses are not pancake short 7-10 cm.
Perhaps a low light fixed lens video cube?


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## Kit. (Aug 13, 2020)

KeithBreazeal said:


> My thought is Canon might be designing a sensor where all the sensor's photodiodes are turned off at the desired shutter speed, then read.


That's called "global shutter" and it has its own drawbacks.


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## Treyarnon (Aug 13, 2020)

Could be more of a specialist commercial applications rather then consumer? In a similar vain to their ultra fast/low light/high res sensors.

I mean, a lens extending right up to the sensor kind of rules out IBIS does it not?
But perhaps there are companies out there requireing a specilest camera where this would be helpful


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## AdmiralFwiffo (Aug 14, 2020)

Maybe with leaf-shutters? Perhaps trying to re-shoot Barry Lyndon?


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## SecureGSM (Aug 14, 2020)

Canon Rumors Guy said:


> Continue reading...


oh, a 0-2mm BF lens design? that is for the full frame sensor ILC Canon mobile phone. Ask HarryFilm. He has got all the details on that


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## mb66energy (Aug 14, 2020)

Stuart said:


> Those lenses are not pancake short 7-10 cm.
> Perhaps a low light fixed lens video cube?


... maybe for surveillance applications?
Canon has high res sensors for that application which might need high aperture lenses. No mechanical shutter but global shutter might help to make it more reliable (over 10 years of continuous op) and avoid yello artifacts to keep faces and other details "readable" ...


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## Sharlin (Aug 14, 2020)

Joules said:


> Possible. But it seems silly to make your lens extent less than 20 mm. Does that amount of space saving really matter to some people?



I was mostly joking, but I meant the inner barrel would retract mostly to protect it when unattached. Although I guess it could be fixed and come with a new type of rear lens cap. I presume there are some optical, rather than size, advantages to having a ridiculously short backfocus distance in these designs.


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## jolyonralph (Aug 14, 2020)

mb66energy said:


> ... maybe for surveillance applications?
> Canon has high res sensors for that application which might need high aperture lenses. No mechanical shutter but global shutter might help to make it more reliable (over 10 years of continuous op) and avoid yello artifacts to keep faces and other details "readable" ...


Was just going to say this, looks like something for security/surveillance camera systems. Probably a more profitable market right now than us photographers.


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## mb66energy (Aug 14, 2020)

jolyonralph said:


> Was just going to say this, looks like something for security/surveillance camera systems. *Probably a more profitable market right now than us photographers.*



Agree! - But if that helps to keep Canon not just alive but healthy we will get new great tools and all the excitement before and during releases


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## Mt Spokane Photography (Aug 14, 2020)

We have been wondering what Canon meant when they said that they would launch a new camera concept initiative this fall. Perhaps this is related?


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## Pape (Aug 14, 2020)

Sharlin said:


> I was mostly joking, but I meant the inner barrel would retract mostly to protect it when unattached. Although I guess it could be fixed and come with a new type of rear lens cap. I presume there are some optical, rather than size, advantages to having a ridiculously short backfocus distance in these designs.


Arent optical advantages also size advantages. Less needed correction lenses ,smaller stuff?


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## Daner (Aug 14, 2020)

H. Jones said:


> I'd pretend I would be a little mad as someone who just picked up the R5 and 35mm 1.8 as my everyday compact carry camera, but if Canon released a fixed lens full frame compact 35mm 1.4 camera I would probably still end up with one anyway for the fun of it



LP-E6NH battery, single SD card slot, same sensor, AF system, IBIS, and viewfinder as the R5. I could live with reduced video capabilities and a fixed screen rather than tilty/flippy, but weather sealing would be appreciated.


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## neurorx (Aug 14, 2020)

Hoping for a 35 1.4 and 135 1.4


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## [email protected] canon rumors (Aug 14, 2020)

some sort of industrial QC camera or satellite camera? Or hi res security cam?


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## canonnews (Aug 15, 2020)

SwissFrank said:


> Setting aside the 0.00mm model, these could theoretically be mounted on the R. I suppose some current RF lenses already extend quite a ways into the camera. I had the Contax G2 in the 90s, and its 16/8 lens was almost entirely inside the camera. In the early 70s I think all the big companies had 21mm lenses for their SLRs that required you lock up the mirror before shooting, because they extended into the camera. (21mm being just over 90 degrees and good for capturing an entire room in a photo.)



not really. There is the shutter assembly in front of the sensor on an R.

on a SLR a lens ingress would hit the mirror long before it would hit the shutter.


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## canonnews (Aug 15, 2020)

[email protected] canon rumors said:


> some sort of industrial QC camera or satellite camera? Or hi res security cam?


curious note is that they usually state something like this or automotive applications. but it's decidedly full frame, which is odd, and as far as "purposes of illustration of use" they show a camera. So I don't know. I do know they are completeyl bizzare designs that i've never seen the like before.


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## Berowne (Aug 15, 2020)

canonnews said:


> curious note is that they usually state something like this or automotive applications. but it's decidedly full frame, which is odd, and as far as "purposes of illustration of use" they show a camera. So I don't know. I do know they are completeyl bizzare designs that i've never seen the like before.



Thanks for your information about theses lenses. 

In 1966 Zeiss introduced a lens called Hologon in two versions a 15mm f8 and a 16mm f8. The 15mm/f8 lens was designed as fixed lens for an analog "full format" camera (there also existed large format versions as prototypes for the Linhof Technica). The back focal length of the 15mm lens was 4,5mm.
From the series of articles on lens names: Distagon, Biogon and Hologon  (pg. 13)

Greetings from Frankfurt am Main - Andy


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## Eclipsed (Aug 15, 2020)

KeithBreazeal said:


> I think I know where Canon is heading with this. The electronic shutter has several issues, especially sports or panning. Canon may be on the way to a totally new method of reading the sensor. Currently, the sensor is read while it is still gathering photons. My thought is Canon might be designing a sensor where all the sensor's photodiodes are turned off at the desired shutter speed, then read. If this is where they are heading, there will be no need for the mechanical shutter, it will allow lens designs with minimal rear element to sensor distance. The closer the rear element is to the sensor, aberrations like Chromatic, Coma, and Spherical will be greatly reduced. If a lens has a minute amount of aberrations at the exit of the last element, the distance to the sensor is the key. Kind of like light going through a prism- the further away the prism is from the viewing surface, the wider the rainbow.(more noticeable Chromatic aberration) The final result is higher resolution and better contrast.


Almost as if the sensor were immersed within the rear element


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## KeithBreazeal (Aug 15, 2020)

Off on another tangent... 
If the rear element was as close to the imaging sensor as possible, the lens's IS corrections for camera shake would be more effective due to shorter distance traveled from the IS elements to the image plane. Depending on the focal length of the lens and where the IS lens group distance from the focal plane, the len's IS could be more effective by a great percentage. By having the rear element deep inside the body, it may be possible to have the IS as far back as the lens mount. This would(depending on the lens) give a few more stops of effective stabilization. Coupled with IBIS, that would be huge advantage for hand held photo and video shooters.


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## Antono Refa (Aug 15, 2020)

KeithBreazeal said:


> Off on another tangent...
> If the rear element was as close to the imaging sensor as possible, the lens's IS corrections for camera shake would be more effective due to shorter distance traveled from the IS elements to the image plane. Depending on the focal length of the lens and where the IS lens group distance from the focal plane, the len's IS could be more effective by a great percentage. By having the rear element deep inside the body, it may be possible to have the IS as far back as the lens mount. This would(depending on the lens) give a few more stops of effective stabilization. Coupled with IBIS, that would be huge advantage for hand held photo and video shooters.



Can IBIS be used with such short back focus?

If the distance is zero, the sensor touches the back element, and can't move at all.

With the limitations of electronics and mount (back element can't be bigger than the throat diameter of 54mm, and light hitting at an oblique angle not reaching the photosites), I'm not sure effective IBIS can be designed if the lens is .5mm from the sensor.


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## Dragon (Aug 16, 2020)

Interesting that the 35 is much longer overall than the 50s even though it has 0 BF distance. These could be for low light security cameras. Properly placed, one 8k FF camera could cover a lot of real estate.


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## fox40phil (Aug 16, 2020)

They should invent more R&D into DO lenses with fixed aperture like f4.0 or 5.6


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## canonnews (Aug 16, 2020)

SwissFrank said:


> To be clear I'm talking about some old SLR lenses that required you to lock up the mirror before use. They came with an external viewfinder you put on the hotshoe. IIRC all the main brands made such a 21mm maybe late 60s/early 70s.


yes, but SLRs had a backfocus distance of over 40mm.

the R has a backfocus distance of 20mm, you can't get to 0mm to 3.5mm because there's a shutter in front of the sensor.

you can get 10-20mm back on an SLR lens without hitting the shutter because you are still ~20mm away from the film plane / sensor, you have to mirror lockup, but that's something different.


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## Dragon (Aug 16, 2020)

Mt Spokane Photography said:


> We have been wondering what Canon meant when they said that they would launch a new camera concept initiative this fall. Perhaps this is related?
> 
> 
> 
> View attachment 192142


That is one possibility that could be quite interesting


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## hne (Aug 17, 2020)

canonnews said:


> yes, but SLRs had a backfocus distance of over 40mm.
> 
> the R has a backfocus distance of 20mm, you can't get to 0mm to 3.5mm because there's a shutter in front of the sensor.
> 
> you can get 10-20mm back on an SLR lens without hitting the shutter because you are still ~20mm away from the film plane / sensor, you have to mirror lockup, but that's something different.



You could, and it's not too different. You'd have to lock up the shutter and use electronic shutter only.


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## Dragon (Aug 20, 2020)

SwissFrank said:


> a problem is you don't want the security camera to be so valuable that people just come in to steal the camera


Not a problem if you mount it between remote controlled twin 50's .


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