Patent: Some very strange full frame lenses

Canon Rumors Guy

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    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)

    Focal length: 51.50mm
    F-number: 1.24
    Half angle of view: 22.79°
    Image height: 21.64mm
    Total lens length: 78.83mm
    BF: 0.50mm

    Canon 50mm f/1.6 (Full Frame)

    Focal lengt:h 49.17mm
    F-number: 1.65
    Half angle of view: 23.75°
    Image height: 21.64mm
    Total lens length: 72.35mm
    BF...

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    Joules

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    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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    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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    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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    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

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    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

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    ... 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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    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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