Canon Patent: 180mm F3.5 Macro, 300mm F4 Macro, And 100mm F4 Macro

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Canon patent application 2024103311 (Japan, published 08/01/2024) discusses method and optical formulas for three telephoto macro lenses:

  • 180mm F3.5 Macro
  • 300mm F4 Macro
  • 100mm F4 Macro

From the patent literature:

  • An optical system that is compact overall and has a small and lightweight focus lens group is provided.
  • [Background Art]In optical systems called macro lenses (microlenses) used for close-up photography, a floating method in which two or more lens groups are moved during focusing is often adopted in order to suppress aberration fluctuations during focusing. Another focusing method is the inner focus method in which focusing is performed by moving an intermediate group of the optical system.
  • In order to reduce the size and weight of the lens group used for focusing, it is important not only to adopt the inner focus method but also to appropriately configure the lens group arranged on the object side of the focus lens group and the lens group used for focusing. In addition, in order to reduce the size of the optical system and reduce aberration fluctuations during focusing, it is important to appropriately set the arrangement, refractive power, and movement amount of the lens group arranged on the object side of the focus lens group and the focus lens group. In the optical systems of Patent Documents 1 and 2, none of these are appropriately set, and the size of the optical system and the size and weight of the focus lens group are not sufficiently reduced.
  • The present invention provides an optical system which is small overall, has a small and lightweight focus lens group, and has high optical performance over the entire object distance, and an image pickup apparatus equipped with the same.

Example 1

  • Focal length: 179.96
  • F-number: 3.60
  • Half angle of view: 6.86
  • Image height: 21.64
  • Overall length: 171.15
  • Back focal length: 26.35
  • Magnification: -1.0

Example 2

  • Focal length: 299.99
  • F-number: 4.12
  • Half angle of view: 4.12
  • Image height: 21.64
  • Total length: 210.00
  • Back focal length: 38.69
  • Magnification: -1.0

Example 3

  • Focal length: 188.87
  • F-number: 4.00
  • Half angle of view: 6.53
  • Image height: 21.64
  • Total length: 188.87
  • Back focal length: 32.67
  • Magnification: -2.0

Example 4

  • Focal length: 235.51
  • F-number: 4.12
  • Half angle of view: 5.25
  • Image height: 21.64
  • Total length: 202.50
  • Back focal length: 66.52
  • Magnification: -1.0

Example 5

  • Focal length: 110.03
  • F-number: 4.12
  • Half angle of view: 11.12
  • Image height: 21.64
  • Overall length: 110.03
  • Back focal length: 17.52
  • Magnification: -1.0
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Canon Patent: RF 300mm f/2.8 IS And RF 400mm f/2.8 IS

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And yet another Canon patent application: two telephoto fast primes for the RF mount.

Canon patent application 2023104022 (Japan, published 7/28/2023) discusses optical formulas for two fast telephoto prime lenses for the RF mount: RF 300mm f/2.8 IS and RF 400mm f/2.8 IS.

From the patent literature:

Optical System and Imaging Device Having the Same

Description of the Related Art

An optical system used in an imaging apparatus is required to be compact and lightweight as a whole, and to have high optical performance capable of satisfactorily correcting various aberrations including chromatic aberration. As a compact optical system, a so-called telephoto type optical system is known in which a lens group with positive refractive power is arranged on the object side and a lens group with negative refractive power is arranged on the image side. However, in the telephoto type optical system, the longer the focal length, the larger the entire system, and the use of a lens with a large diameter or a heavy lens tends to increase the weight of the entire optical system.

Example 1

  • Focal length: 294.99
  • F-value: 2.90
  • Half angle of view: 4.19
  • Image height: 21.64
  • Overall length: 280.25
  • Back focus: 37.47

Example 2

  • Focal length: 390.00
  • F-value: 2.90
  • Half angle of view: 3.18
  • Image height: 21.64
  • Overall length: 370.50
  • Back focus: 37.00

More Canon patents are listed here.

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Is Canon Developing A Mirror Lens With Auto-Focus?

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That’s what a Canon patent application seems to suggest, a 300mm f/2.3 mirror lens. Read on.

Canon patent application 2023013456 (Japan, published 1/26/2023) discusses optical formulas for a 300mm f/2.3 mirror lens with autofocus. From the patent literature:

An optical system capable of sufficiently correcting curvature of field while being compact, lightweight, and having a large aperture ratio is provided.

Description of the Related Art

As a telephoto imaging optical system having a long focal length, there is a catadioptric imaging optical system having a reflective system and a refracting system. In such a catadioptric imaging optical system, Patent Literatures 1 and 2 disclose an inner focus type imaging optical system that is compact, lightweight, has a large aperture ratio, and has an autofocus function. ing. [0004]However, in the imaging optical systems disclosed in Patent Documents 1 and 2, the configuration of the reflection system cannot sufficiently correct the curvature of field.

SUMMARY OF THE INVENTION

The present invention provides an optical system capable of sufficiently correcting curvature of field while having a small size, light weight, and large aperture ratio.

An optical system as one aspect of the present invention has a first group that does not move during focusing and a second group that moves during focusing.

Example 1

  • Focal length: 298.89
  • F-value: 2.28
  • Half angle of view: 4.14
  • Image height: 21.64
  • Overall length: 177.20
  • Back focus: 65.95

Example 2

  • Focal length: 408.04
  • F-value: 5.00
  • Half angle of view: 3.04
  • Image height: 21.64
  • Total length: 189.17
  • Back focus: 47.69

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

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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.

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Canon RF 300mm f/2.8L IS To Get Announced Soon?

Eos R6 Mark Iii Nab 2023 Canon Eos R5 Mark Ii Canon Eos R8 CP+ 2024 Mark Ii Canon EOS Rf 24-50mm R6 Mark Ii Rf Mount Eos R6 Mark Ii Rf 300mm Rf 35mm Canon Eos R100 Rf 24mm F/1.8 Rf-s Canon Eos R7 Eos R100 Canon High Resolution Eos R R10 Eos C5 Canon Canon Eos R1 Eos R5c Canon Rf 16mm Rf 35mm F/1.2L EF Lenses Tilt-shift Lenses Rumor
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A new rumor, about the Canon RF 300mm f/2.8L IS lens. Is it coming? The EF version is discontinued.

A rather confident rumor suggests that Canon might be close to announce the Canon RF 300mm f/2.8L IS lens. Says the source of the rumor:

[…] Canon has prototypes out in the wild and that the lens is a ground-up redesign of the focal length.

[…] weight has been reduced by almost 40% and  the length by as much as 30% over it’s EF predecessor, though they didn’t have the exact dimensions and weight to give us.

The lens is rumored to get announced at the beginning of 2023.

Stay tuned.

Source: Canon Rumors

Canon Patent: 200mm f/2, 300mm f/2.8 And 500mm f/4 (RF mount?)

Canon Patent
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Canon patent application for some telephoto zooms, for the EOS R system I guess.

Canon patent application 2020196094 (Japan) discusses optical formulas for three telephoto zoom lenses:

  • 200mm f/2
  • 300mm f/2.8
  • 500mm f/4

As a shooting optical system having a long focal length, a so-called telephoto type shooting optical system is known. The telephoto type photographic optical system is used, for example, in a single focus super-telephoto lens.

In the photographing optical system described in Patent Document 1, the second lens group having a negative refractive power is moved during focusing. Here, the second lens group is arranged at a position relatively close to the first lens group, and it cannot be said that the focus group can be sufficiently reduced in size and weight.

An object of the present invention is to provide an optical system that is lightweight and has chromatic aberration and other aberrations satisfactorily corrected, and an image pickup apparatus having the same.

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

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