Canon Patent: Smaller Form Factor For Built-in Teleconverter

Canon Patent

Here is a new Canon patent application. I rather interesting one.

Canon patent application 2023118490 (Japan, published 8.25.2023) discusses methods and technology for a built-in teleconverter with a smaller form factor, i.e. the miniaturization of the teleconverter.

From the patent literature:

A large space is required for inserting or retracting a conversion lens inside an optical device, making it difficult to miniaturize the optical device.

Description of the Related Art

In optical equipment such as digital cameras, video cameras, and interchangeable lenses, it is known that the focal length range can be changed by inserting a conversion lens into the optical path.

Patent Document 1 discloses a technique for moving a conversion lens built into a camera body between an insertion position inserted into an optical path and a retracted position retracted out of the optical path. The built-in conversion lens described here is retracted in the space between the prism that guides the subject image to the finder and the strobe that is stored above the lens barrel.

However, the built-in conversion lens described in Patent Document 1 is moved to the retracted position using a dedicated actuator. Therefore, a space for arranging the actuator inside the lens is required, and it is difficult to suppress the enlargement of the lens.

Accordingly, the present invention provides an optical apparatus that has a built-in conversion lens so that a space for inserting or withdrawing the built-in conversion lens can be secured while suppressing an increase in the size of the lens. for the purpose.

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Canon Patent: 15-70mm F2.8-4 IS, 15-70mm F4 IS And 15-85mm F2.8-5.6 IS for APS-C

Canon Patent

A new Canon patent application for three lenses for the RF mount and cameras with APS-C imaging sensor.

Canon patent application 2022013994 (Japan, published 8/14/2023) discusses optical formulas for three RF-mount lenses for APS-C imaging sensors:

  • 15-70mm F2.8-4 IS
  • 15-70mm F4 IS
  • 15-85mm F2.8-5.6 IS

From the patent literature:

A compact zoom lens with a wide angle of view is provided that is robust against manufacturing errors and yet provides high optical performance.

Description of the Related Art

In recent years, there has been a strong demand for a lens system used in an imaging apparatus to have high optical performance while the entire lens system is compact. In order to achieve good optical performance while miniaturizing the entire lens system, it is important to appropriately set the refractive power and configuration of each lens group, and the conditions for moving each lens group during zooming. In particular, when miniaturizing the lens system of a camera with a large image sensor, high refractive index glass materials are often used, and it is required to suppress chromatic aberration while ensuring robustness against decentration of the lens.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a compact zoom lens or the like with a wide angle of view that provides high optical performance while being robust against manufacturing errors. In the zoom lens of each embodiment, any one of the lens groups as a whole or a part thereof is moved so as to include a component in the direction perpendicular to the optical axis as an anti-vibration group, or in an in-plane direction including the optical axis. It is also possible to employ a configuration in which vibration isolation is performed by rotationally moving (oscillating). In particular, it is preferable to use the cemented lens B as the anti-vibration group.

Example 1 (15-70mm F4, for APS-C)

  • Zoom ratio 4.40
  • Focal length 15.45 36.03 67.94
  • F value 4.12 4.12 4.12
  • Half angle of view 41.27 19.59 10.60 Image
  • height 12.66 13.66 13.66
  • Total lens length 100.14 108.00 120.23
  • Back focus 10.46 10.79 12.37

Example 2 (15-70mm F2.8-4, for APS-C)

  • Zoom ratio 4.40
  • Focal length 15.45 36.49 68.04
  • F number 2.88 3.86 4.12
  • Half angle of view 41.38 19.53 10.61 Image
  • height 12.66 13.66 13.66
  • Lens length 100.32 11 0.44 118.71
  • Back focus 10.62 11.68 15.59

Example 3 (15-85mm F2.8-5.6, for APS-C)

  • Zoom ratio 5.42
  • Focal length 15.45 36.29 83.77
  • F value 2.88 4.00 5.80
  • Half angle of view 41.36 19.65 8.71
  • Image height 12.66 13.66 13.66
  • Total lens length 101.54 1 16.35 133.85
  • Back focus 12.12 12.61 16.91

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Canon Patent: 800mm f/5.6 IS, 1000mm f/8 IS And 1200mm f/8 IS Lenses

Canon Patent

A new Canon patent application. Canon patent application 2023107573 (Japan, published 8/3/2023) discusses optical formulas for three telephoto lenses:

  • 800mm f/5.6 IS
  • 1000mm f/8 IS
  • 1200mm f/8 IS

From the patent literature:

An object of the present invention is to provide an optical system in which various aberrations are satisfactorily corrected while being compact and lightweight, and an imaging apparatus having the optical system.

Description of the Related Art

A telescopic optical system used in an imaging apparatus is required to have a long focal length and a small F-number (large aperture). Patent Documents 1 and 2 disclose a first lens group with positive refractive power, a second lens group with positive or negative refractive power, and a third lens group with positive or negative refractive power, which are arranged in order from the object side to the image side. An optical system is disclosed, consisting of lens groups, with a second lens group moving during focusing.

Here, it is also desired that the telescopic optical system be compact and lightweight, and that various aberrations such as chromatic aberration and spherical aberration are well corrected. However, when trying to increase the aperture of a telescopic optical system, the effective diameter of the lens arranged on the object side becomes particularly large, making it difficult to reduce the size and weight of the entire system. Therefore, in order to realize the above-mentioned demands, it is important to appropriately set the optical arrangement of each lens group that constitutes the optical system, and the refractive power and arrangement of each lens that constitutes each lens group.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optical system in which
various aberrations are satisfactorily corrected while being compact and lightweight, and an imaging apparatus having the optical system.

Example 1

  • Focal length: 820.00
  • F-value: 5.90
  • Half angle of view: 1.51
  • Image height: 21.64
  • Total length: 437.08
  • Back focus: 88.12

Example 2

  • Focal length: 1180.10
  • F-value: 8.00
  • Half angle of view: 1.05
  • Image height: 21.64
  • Total length: 550.00
  • Back focus: 140.36

Example 3

  • Focal length: 1000.0
  • F-value: 8.00
  • Half angle of view: 1.24
  • Image height: 21.64
  • Total length: 477.48
  • Back focus: 115.01

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Canon Patent: RF 24-300mm f/2.8-5.6 IS, RF 24-240mm f/2-5.6 IS And RF 40-350mm f/2.8-5.6 IS

Canon Patent

And another Canon patent for lenses for the RF mount.

Canon patent application 2023104137 (Japan, published 7/28/2023) discusses optical formulas for three zoom lenses for the RF mount:

  • RF 24-300mm f/2.8-5.6 IS
  • RF 24-240mm f/2-5.6 IS
  • RF 40-350mm f/2.8-5.6 IS

From the patent literature:

A zoom lens, an imaging device having the same, and an imaging system

To provide a zoom lens that is compact as a whole, has a high zoom ratio, and has high optical performance over the entire zoom range.

BACKGROUND ART

In recent years, there has been a demand for a zoom lens used in an imaging apparatus having an imaging device to have a compact overall system, a high zoom ratio, and high resolution (high optical performance). . In particular, zoom lenses are required to have high optical performance with substantially uniform resolving power from the center of the screen to the periphery of the screen.

However, in the zoom lenses disclosed in Patent Documents 1 and 2, since the relationship between the refractive powers of the lens groups is not appropriate, the lens size increases when the zoom ratio is increased, and astigmatism at the wide-angle end and coma at the telephoto end gets worse.

The present invention provides a zoom lens that is compact overall, has a high zoom ratio, and has high optical performance over the entire zoom range.

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Canon Patent: RF 300mm f/2.8 IS And RF 400mm f/2.8 IS

Canon Patent

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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Canon Patent: RF 15mm f/2 And RF 12mm f/2.8 Lenses

Canon Patent

And here is another Canon patent application, for two RF mount lenses.

Canon patent application 023104029 (Japan, 7/28/2023) discusses optical formulas for two fast prime lenses for the RF mount: RF 15mm f/2 and RF 12mm f/2.8.

From the patent literature:

Optical System and Imaging Device Having the Same

A wide-angle lens is provided that is compact and lightweight, and provides a high optical performance in which fluctuations in aberration due to focusing are suppressed while a high photographing magnification can be obtained at the time of photographing at the shortest distance.

Description of the Related Art

In recent years, there has been a demand for wide-angle lenses used in imaging apparatuses that are compact as a whole and that are capable of obtaining a high photographing magnification at the time of photographing at the shortest distance. In addition, there is a demand for a lens having high optical performance in focusing from infinity to the closest object.

In a wide-angle lens, in order to obtain a high photographing magnification at the time of photographing at the shortest distance, it is necessary to increase the amount of movement of the focus lens group, which makes it difficult to reduce the size of the entire lens. In order to reduce the amount of movement of the focus lens group, it is necessary to increase the refractive power of the focus lens group.

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