Canon Patent: RF 70-200mm F2-2.8 DS, RF 70-135mm F2.5 DS, More Lenses

A new Canon patent application for RF mount lenses with “Defocus Smoothing” (DS) optical technology. More about Defocus Smoothing is listed here.

Canon patent application 2023170260 (Japan, published 12/1/2023) discusses optical formulas for a bunch of RF mount lenses:

All, apparently, have DS on board. From the patent literature:

An object of the present invention is to provide a variable power optical system that obtains a uniform and good apodization effect over the entire zoom range and suppresses peripheral dimming.
Background Art
Conventionally, in order to obtain an appropriately blurred image, an optical system equipped with a filter having a transmittance distribution, such as an apodization filter whose transmittance changes as the distance from the optical axis increases, has been known. There is. Patent Document 1 discloses an optical system in which apodization filters are arranged before and after the aperture of a single focus lens.
However, since the optical system disclosed in Patent Document 1 is a single focus optical system, it is insufficient as a method for obtaining a sufficient apodization effect in each zoom state of a variable power optical system. Further, in a variable magnification optical system, it is required to suppress peripheral dimming and to obtain a good apodization effect during variable magnification.
Accordingly, an object of the present invention is to provide a variable power optical system that obtains a good apodization effect over the entire zoom range and suppresses peripheral dimming.

Example 1