Canon Patent: 300mm f/2.8, 400mm f/2.8 And 600mm f/4 With Built-in Teleconverter

Canon Patent

A new Canon patent for telephoto lenses with built-in teleconverter. For what mount? RF mount.

Canon patent 2022142979 (Japan, published 10/3/2022) discusses optical formulas for three telephoto lenses with built-in teleconverter. The lenses are 300mm f/2.8, 400mm f/2.8 and 600mm f/2.8. From the patent literature (machine translated):

An object of the present invention is to provide an optical system having a variable power optical system that is inserted into and removed from a main optical system, and to achieve good optical performance while reducing the weight of the entire system.

Description of the Related Art

As a method for changing the focal length of an optical system used in an imaging apparatus, there is a converter method that changes the focal length of the entire system by inserting a variable magnification optical system (extender) in the optical path.

When adopting a system incorporating a variable magnification optical system, in order to achieve good optical performance while reducing the weight of the entire system including the variable magnification optical system, the insertion position of the variable magnification optical system must be appropriately selected. It is important not only to do so, but also to properly configure the main optical system. The invention disclosed in Patent Document 1 has room for improvement from the viewpoint of achieving both weight reduction and optical performance.

Summary of the invention

It is an object of the present invention to achieve good optical performance while reducing the weight of the entire system in an optical system having a variable magnification optical system that is inserted into and removed from a main optical system.

Example 1 ML

  • Focal length: 389.00
  • F-value: 2.91
  • Half angle of view: 3.18
  • Image height: 21.64
  • Total length: 406.00
  • Back focus: 53.83

Example 1 with teleconverter

  • Focal length: 544.00
  • F-value: 4.19
  • Half angle of view: 2.28
  • Image height: 21.64
  • Overall length: 406.01
  • Back focus: 53.83

Example 2 ML

  • Focal length: 582.00
  • F-value: 4.12
  • Half angle of view: 2.13
  • Image height: 21.64
  • Overall length: 486.10
  • Back focus: 81.91

Example 2 with teleconverter

  • Focal length: 814.80
  • F-value: 5.88
  • Half angle of view: 1.52
  • Image height: 21.64
  • Overall length: 486.10
  • Back focus: 81.91

More Canon patents are listed here.

[via asobinet]

Canon Patent: 200-500mm f/4 and 300-800mm f/8 Lenses

Canon Patent

A new Canon patent was spotted. The patent refers to two super zoom lenses. Again, as it seems, for the RF mount

Canon patent application 2022/0035144 (USA) discusses optical formulas for a 200-500mm f/4 lens and a 300-800mm f/8 lens. Other lenses discussed in the patent literature are 200-400mm f/4 and 150mm f/5 – 600mm f/6.5. These too might be for the RF mount.

Example 1

  • Focal length: 206.00-485.01
  • F value: 4.09-4.10
  • Half angle of view: 6.00-2.55
  • Image height: 21.64
  • Overall length: 486.99
  • Back focus: 53.96

Example 3

  • Focal length: 154.55-585.00
  • F value: 5.10-6.51
  • Half angle of view: 7.97-2.12
  • Image height: 21.64
  • Overall length: 288.00-388.00
  • Back focus: 15.00-95.75

Example 4

  • Focal length: 205.00-390.00
  • F value: 4.10
  • Half angle of view: 6.02-3.18
  • Image height: 21.64
  • Overall length: 367.09
  • Back focus: 46.68

Example 5

  • Focal length: 305.00-774.99
  • F value: 8.09-8.10
  • Half angle of view: 4.06-1.60
  • Image height: 21.64
  • Overall length: 489.78
  • Back focus: 100.04

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

[via asobinet.com]

Canon Patent: RF 100-400mm f/5.0-7.1, RF 100-300mm f/5.6-8.2

Canon Patent

Here is another Canon patent application, as usual spotted by asobinet.com. Two more RF-mount lenses are discussed.

The Canon patent application discusses optical formulas for RF 100-400mm f/5.0-7.1, RF 100-300mm f/5.6-8.2 and RF-S 55-250mm f/4.5-7.1 lenses. Note that the last one has an “RF-S”.

The RF 100-400mm f/5.0-7.1 and RF 100-300mm f/5.6-8.2 seem to be inexpensive telephoto lenses for a full frame mirrorless camera, i.e. the EOS R. The RF-S 55-250mm f/4.5-7.1 is clearly designed for an APS-C sensor, according to asobinet.com. Hence, it might be for the EOS M system, or for the fabled EOS R with crop sensor.

Embodiment 1:

  • Wide-angle intermediate telephoto
  • Focal length 103.00 200.00 388.50
  • F number 5.00 6.26 7.10
  • Half angle of view (degrees) 11.86 6.17 3.19
  • Image height 21.64 21.64 21.64
  • Lens overall length 215.58 255.38 293.58
  • BF 38.40 58.61 78.01

Embodiment 2:

  • Wide-angle intermediate telephoto
  • Focal length 103.01 200.00 388.50
  • F number 5.00 6.45 7.10
  • Half angle of view (degrees) 11.86 6.17 3.19
  • Image height 21.64 21.64 21.64
  • Lens overall length 207.99 243.96 285.99
  • BF 45.82 78.95 112.66

Embodiment 3:

  • Wide-angle intermediate telephoto
  • Focal length 103.00 200.00 388.48
  • F number 5.18 6.70 8.24
  • Half angle of view (degrees) 11.86 6.17 3.19
  • Image height 21.64 21.64 21.64
  • Lens overall length 203.50 243.44 273.50
  • BF 41.10 76.59 114.00

Embodiment 4 (for APS-C sensor):

  • Wide-angle intermediate telephoto
  • Focal length 56.66 120.00 242.50
  • F number 4.66 6.45 7.10
  • Half angle of view (degrees) 13.55 6.49 3.22
  • Image height 13.66 13.66 13.66
  • Lens overall length 129.73 155.54 184.73
  • BF 19.19 43.59 64.21

Ideas and comments are welcome.

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

Canon Patent: Various Telephoto Zoom Lenses For The RF Mount

Telephoto Zoom

And here is another Canon patent application for telephoto zoom RF mount lenses. No doubt left that Canon is heavily investing in the EOS R full frame mirrorless system.

Canon patent application P2021-56407A (Japan) discusses optical formulas and designs for a bunch of telephoto zoom lenses for the RF mount. However, one of the optical designs listed below is for an APS-C sensor, so either for the EOS M (likely) or for Canon’s crop sensor DSLR lineup. The patent application was spotted by Hi Lows Note.

Embodiment 1

  • Zoom ratio 2.68
  • Focal length 72.27 135.02 193.89 mm
  • F number 4.08 4.08 4.12
  • Half angle of view(°) 16.67 9.10 6.37
  • Image height 21.64 21.64 21.64 mm
  • Lens length 137.50 175.84 193.12 mm
  • BF 14.44 24.23 29.66 mm

Embodiment 2

  • Zoom ratio 4.82
  • Focal length 101.59 200.00 490.00 mm
  • F number 4.60 5.09 6.80
  • Half angle of view(°) 12.02 6.17 2.53
  • Image height 21.64 21.64 21.64 mm
  • Lens length 222.29 279.43 312.29 mm
  • BF 21.06 29.20 64.12 mm

Embodiment 3

  • Zoom ratio 2.69
  • Focal length 72.13 100.00 194.06 mm
  • F number 2.89 2.89 2.91
  • Half angle of view(°) 16.70 12.21 6.36
  • Image height 21.64 21.64 21.64 mm
  • Lens length 161.59 187.06 220.03 mm
  • BF 15.86 20.68 31.81 mm

Embodiment 4 (for APS-C sensor)

  • Zoom ratio 4.24
  • Focal length 56.90 130.00 241.30 mm
  • F number 4.68 5.88 6.55
  • Half angle of view(°) 13.50 6.00 3.24
  • Image height 13.66 13.66 13.66 mm
  • Lens length 102.01 140.24 153.08 mm
  • BF 13.47 21.19 39.32 mm

Embodiment 5

  • Zoom ratio 3.75
  • Focal length 103.39 196.91 387.69 mm
  • F number 5.77 7.10 8.24
  • Half angle of view(°) 11.82 6.27 3.19
  • Image height 21.64 21.64 21.64 mm
  • Lens length 165.42 201.96 235.42 mm
  • BF 13.85 33.27 57.50 mm

Embodiment 6

  • Zoom ratio 3.88
  • Focal length 100.04 198.04 387.80 mm
  • F number 5.77 7.10 8.24
  • Half angle of view(°) 12.20 6.23 3.19
  • Image height 21.64 21.64 21.64 mm
  • Lens length 159.40 202.97 229.40 mm
  • BF 10.02 28.12 62.23 mm

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

Canon EF 200mm f/2L IS Review – A Legendary Lens That Might Get Discontinued

EF 200mm F/2L IS Review

Here is a Canon EF 200mm f/2L IS review. The Canon EF 200mm f/2L IS is a remarkable lens but now it seems Canon might discontinue it soon.

At a glance:

  • EF-Mount Lens/Full-Frame Format
  • Aperture Range: f/2 to f/32
  • Fluorite & Ultra-Low Dispersion Elements
  • Super Spectra Coating
  • Ring-Type Ultrasonic Motor AF System
  • Optical Image Stabilizer
  • Weather-Sealed Construction
  • Detachable, Rotatable Tripod Collar
  • Rounded 8-Blade Diaphragm

Christopher Frost posted his Canon EF 200mm f/2L IS review. This classic Canon telephoto lens was introduced in 2008, and now it seems that Canon is set to discontinue it in favor of an RF mount version. At least that’s what recent rumors suggests, and indeed the Canon EF 200mm f/2L IS shows up as discontinued at B&H Photo. You can still find it at Amazon.

Canon EF 200mm f/2L IS:

America: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA
Europe & UK: Amazon DE, Amazon UK, Amazon IT, Canon IT, WEX Photographic, Canon FR, Canon UK, Canon DE

Click here to open the rest of the article

Canon Patent For Big Telephoto Lenses, Likely For The Canon EOS R System

Canon Patent

Canon patent application 2019-0339497 (USA) discusses optical formulas for 500mm f/4, 300mm f/2.8, 400mm f//4, and 800mm f/5.6 lenses for the Canon EOS R full frame mirrorless system. At least likely.

The optical formulas discusses in the patent might as well refer to the EF mount. We are not sure about this, though we tend to think the lenses are for the EOS R system. All lenses seem to have internal focusing.

You can download the patent:

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