Canon Patent: RF Mount Prime Lenses With Defocus Smoothing

Canon Patent

A new Canon patent application. Three fast primes are discussed, all seem to have Defocus Smoothing on board.

Defocus Smoothing is an optical technology introduced first on the RF 85mm f/1.2 DS. Canon patent application 2021-196547 (Japan) discusses optical formulas for the following lenses:

  • 50mm F1.4
  • 135mm F1.4
  • 24mm F1.4

All three lenses have Defocus Smoothing. From the patent literature:

PROBLEM TO BE SOLVED: To provide an optical system having high wavelength uniformity in a pupil surface.

As an optical element used in an optical device, an ND (Neutral Density) filter for adjusting the amount of transmitted light is known. In particular, in order to improve the variation in sharpness of the contour of the out-of-focus image (blurred image) (to obtain the apodization effect), a gradation type ND filter (GND filter, apodization filter) having different transmittance for each region is used. Be done. Patent Document 1 describes a GND filter in which an apodization effect is obtained by using a film whose thickness changes for each region.

However, in Patent Document 1, the uniformity (wavelength uniformity) of the transmittance distribution on the pupil surface with respect to the wavelength when the GND filter is applied to the optical system is not considered.

The optical system as one aspect of the present invention is an optical system having an optical element including a first region in which the transmittance changes in the radial direction, and the optical element is an optical axis perpendicular to the radial direction. A substrate arranged along the direction and a first layer are provided, the maximum incident angle of an axial marginal ray with respect to an optical surface included in the optical system is θm, and the extinction coefficient of the first layer at a wavelength of 550 nm.

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

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Canon Patent: More Fast Prime Lenses For The RF Mount

Canon Patent

And yet another Canon patent application for a bunch of fast prime lenses for the RF mount, i.e. for the EOS R full frame mirrorless camera system.

Canon patent application 2021-193406 (Japan) aims to

[…] provide an optical system having high optical performance and less aberration fluctuation due to focusing.

and discusses optical formulas for these lenses:

  • RF 18mm F1.8
    • Focal length 18.54
    • F number 1.85
    • Half angle of view (°) 49.41
    • Image height 21.64
    • Lens total length 107.66
    • BF 14.09
  • RF 20mm F1.4
    • Focal length 20.48
    • F number 1.44
    • Half angle of view (°) 46.56
    • Image height 21.64
    • Lens total length 124.66
    • BF 13.16
  • RF 24mm F1.8
    • Focal length 23.83
    • F number 1.85
    • Half angle of view (°) 42.24
    • Image height 21.64
    • Lens total length 104.66
    • BF 15.90
  • RF 28mm F1.8
    • Focal length 28.08
    • F number 1.85
    • Half angle of view (°) 37.61
    • Image height 21.64
    • Lens total length 92.66
    • BF 12.16

Keep in mind that the mere existence of a patent application doesn’t necessarily entail the described item will ever hit the market. Time will tell.

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

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Canon Patent: 35-600mm f/4-7.2 Zoom Lens For The RF Mount

Canon Patent

Here is a new Canon patent application. As so often lately, this one too refers to an RF mount lens.

Canon patent application 2021-193435 (Japan) discusses optical formulas for what could be a very interesting zoom lens for EOS R photographers. Indeed, it could be the mother of all zoom lenses. A RF 35-600mm f/4-7.2 zoom lens (example 4, below) is discussed in the patent literature (along with a 24-300mm lens).

Example 1:

  • Focus focal length 24.74 76.74 387.90
  • F number 3.60 5.30 6.50
  • Half angle of view 39.51 15.75 3.19
  • Image height 20.40 21.64 21.64
  • Lens total length 194.51 241.18 287.86
  • BF 13.32 48.47 46.4

Example 2:

  • Focal length 24.72 69.39 289.87
  • F number 3.60 5.30 5.88
  • Half angle of view 39.53 17.32 4.27
  • Image height 20.40 21.64 21.64
  • Lens total length 168.78 202.25 235.73
  • BF 13.34 39.12 36.81

Example 3:

  • Focal length 28.81 94.89 484.70
  • F number 3.60 5.30 7.20
  • Half angle of view 35.30 12.84 2.56
  • Image height 20.40 21.64 21.64
  • Lens total length 194.00 240.17 286.34
  • BF 13.85 43.81 39.37

Example 4:

  • Focal length 33.05 140.67 581.87
  • F number 4.10 5.90 7.20
  • Half angle of view 31.69 8.74 2.13
  • Image height 20.40 21.64 21.64
  • Lens total length 218.72 276.34 333.97
  • BF 14.32 39.28 46.78

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

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Canon Patent: 24-100mm f/2.8 And 24-70mm f/2-3.5

Canon Patent

Here is a new Canon patent application, for a 24-100mm f/2.8 and a 24-70mm f/2-3.5 lens. The design seems to be agnostic, meaning no mount type is specified.

Canon patent application 2021-189218 (Japan) discusses optical formulas for two lenses: 24-100mm f/2.8 and a 24-70mm f/2-3.5.

Example 1

  • Zoom ratio 3.92
  • Wide-angle intermediate telephoto
  • Focal length 24.72 48.69 97.00
  • F number 2.90 2.90 2.90
  • Half angle of view 37.60 23.96 12.57
  • Lens total length 119.56 132.86 152.43
  • BF 5.30 10.90 19.16

Example 2

  • Zoom ratio 2.75
  • Wide-angle intermediate telephoto
  • Focal length 24.72 40.75 67.96
  • F number 2.06 3.50 3.50
  • Half angle of view 37.60 27.97 17.66
  • Lens total length 105.84 115.84 131.74
  • BF 13.77 21.03 28.47

Example 3

  • Zoom ratio 2.75
  • Wide-angle intermediate telephoto
  • Focal length 24.72 40.96 67.96
  • F number 2.90 2.90 2.90
  • Half angle of view 37.60 27.84 17.66
  • Lens total length 93.83 105.51 121.76
  • BF 3.29 10.64 20.42

Example 4

  • Zoom ratio 3.92
  • Wide-angle intermediate telephoto
  • Focal length 24.72 48.16 97.00
  • F number 2.90 3.50 3.50
  • Half angle of view 37.60 24.19 12.57
  • Image height 19.04 21.64 21.64
  • Lens total length 98.44 114.37 139.82
  • BF 3.88 12.29 24.26

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

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Canon Patent: 14-280mm f/2.8-5.6 Lens For 4/3 Sensor

Canon Patent

Does Canon have a 4/3 camera in their lineup? However, here is a Canon patent application for a lens that seems to fit such a sensor.

Canon patent application 2021-183997 (Japan) discusses optical formulas for a 14-280mm f/2.8-5.6 lens for a camera with a 4/3 sensor. From the patent literature:

There are known zoom lenses that are compact and can efficiently obtain a magnification ratio, which are suitable for image pickup devices such as digital cameras, video cameras, and TV cameras. The zoom lens has a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive or negative refractive power in order from the object side to the image side. There is something. In the zoom lens, the lens group on the image side of the third lens group is moved to correct (compensate) the image plane movement due to the scaling.

Example 1

  • Focal length 14.26 117.92 280.89
  • F number 2.88 5.38 5.77
  • Half angle of view (°) 37.19 5.24 2.21
  • Image height 10.82 10.82 10.82
  • Lens total length 181.14 181.14 181.14
  • BF 19.35 10.59 6.46

The patent also describes a lens with 10x zoom. Maybe both lenses are for an upcoming PowerShot-like camera with a 4/3 sensor? Or a video camera?

Example 2

  • Focal length 17.51 ​​87.85 169.87
  • F number 2.27 4.40 4.63
  • Half angle of view (°) 31.70 7.02 3.64
  • Image height 10.82 10.82 10.82
  • Lens total length 129.45 129.45 129.45
  • BF 21.20 11.01 6.13

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

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Canon Patent: More RF Mount Lenses – 14mm f/1.8 & 20mm f/1.4

Canon Patent

And yet another Canon patent application for RF mount lenses. This time we have a 14mm f/1.8 and a 20mm f/1.4.

Canon patent application 2021-184030 (Japan) discusses optical designs for a 14mm f/1.8 and a 20mm f/1.4 lens, both for full frame mirrorless cameras, i.e. for the EOS R lineup.

PROBLEM TO BE SOLVED: To provide a single focus lens which is advantageous in terms of wide angle, small size and high optical performance, for example.

An image pickup optical system used in a photographic camera and a movie camera is required to have a wide angle, a small F value, and an image pickup optical system having substantially uniform resolution from the center of the screen to the periphery of the screen over the entire object distance. ing. In order to realize such an imaging optical system, a first lens group fixed at the time of focusing is arranged on the most object side, and a plurality of negative lenses are continuously arranged from the most object side in the first lens group. A single focus lens (single focus optical system) has been proposed. Patent Document 1 describes a single focal length optical system having a focal length of 24 mm and an F value of 1.4, and Patent Document 2 describes a single focal length optical system having a focal length of 20 mm and an F value of 1.4.

Example 1

  • Focal length 18.46
  • F number 1.73
  • Angle of view 49.53
  • Image height 21.64
  • Lens total length 144.17
  • BF 39.17

Example 2

  • Focal length 14.42
  • F number 1.74
  • Angle of view 56.31
  • Image height 21.64
  • Lens total length 151.49
  • BF 37.99

Example 4

  • Focal length 20.00
  • F number 1.46
  • Angle of view 47.25
  • Image height 21.64
  • Lens total length 146.11
  • BF 38.99

Example 5

  • Focal length 16.00
  • F number 1.74
  • Angle of view 53.52
  • Image height 21.64
  • Lens total length 127.35
  • BF 35.73

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

[via asobinet.com]