Canon Patent: 400mm F4, 500mm F5.6, and 800mm F6.3

Here is anew Canon patent application for three telephoto lenses.

Canon patent application 2024163673 (Japan, published 11/22/2024) discusses optical formulas for three telephoto lenses:

From the patent literature:

A compact optical system is provided that has a sufficient aperture ratio and can effectively correct various aberrations.
Background Art: As a small telephoto lens, an optical system has been disclosed that has a first lens group with positive refractive power, a second lens group with negative refractive power that moves during focusing, and a third lens group with positive refractive power, which are arranged in order from the object side to the image side. In addition, as an optical system advantageous for video shooting and dustproofing and drip-proofing, an optical system employing an inner focus method or a rear focus method in which focusing is performed by moving a lens group on the image side rather than the first lens group, which is the closest to the object side, has been disclosed. These optical systems have good correction of various aberrations such as spherical aberration and chromatic aberration. In addition, the optical system may have an anti-vibration function for reducing (correcting) image blur caused by camera shake such as hand shake. Furthermore, these optical systems are also required to have a large aperture ratio and high optical performance.

Example 1