US 12,256,135 B2
Optical system and image pickup apparatus having the same
Takeo Mori, Tochigi (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Mar. 20, 2023, as Appl. No. 18/186,234.
Claims priority of application No. 2022-046855 (JP), filed on Mar. 23, 2022.
Prior Publication US 2023/0308735 A1, Sep. 28, 2023
Int. Cl. H04N 23/55 (2023.01); G02B 9/08 (2006.01)
CPC H04N 23/55 (2023.01) [G02B 9/08 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An optical system consisting of, in order from an object side to an image side, a front unit, an aperture stop, and a rear unit that has positive refractive power as a whole,
wherein the rear unit includes a final lens disposed closest to an image plane and having positive refractive power, and
wherein the following inequalities are satisfied:
0.5<TTL/Φi<1.4
1.64<PNdave<2.00
2.0<Φp/sk<4.0
where TTL is a distance on an optical axis from a lens surface on an object side of a lens disposed closest to an object in the optical system to the image plane, Φi is a diameter of an image circle, PNdave is an average value of refractive indices for d-line of all positive lenses included in the optical system, Φp is an effective diameter of a lens surface on the image side of the final lens, and skis an air conversion length of a distance on the optical axis from the lens surface on the image side of the final lens to the image plane.