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

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

More Canon patents are listed here.

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