US 12,455,431 B2
Optical system and image capturing apparatus including the same
Takahiro Saito, Tochigi (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Sep. 15, 2022, as Appl. No. 17/932,626.
Claims priority of application No. 2021-154433 (JP), filed on Sep. 22, 2021.
Prior Publication US 2023/0097746 A1, Mar. 30, 2023
Int. Cl. G02B 9/12 (2006.01); G02B 5/00 (2006.01); H04N 25/00 (2023.01)
CPC G02B 9/12 (2013.01) [G02B 5/005 (2013.01); H04N 25/00 (2023.01)] 17 Claims
OG exemplary drawing
 
1. An optical system comprising, in order from an object side to an image side:
a front lens unit with positive refractive power;
an intermediate lens unit; and
a rear lens unit,
wherein the intermediate lens unit moves to change an interval between the front lens unit and the intermediate lens unit and an interval between the intermediate lens unit and the rear lens unit in focusing from infinity to a close range,
wherein the front lens unit includes an aperture stop,
wherein a first partial unit consisting of all lenses disposed on the object side of the aperture stop in the front lens unit includes a biconvex air lens, and
wherein the following inequalities are satisfied:
0.01<fLP/EA<0.80,
0.40<fL2/EA<1.10, and
0.11<Dair/L<0.22
where fLP is a focal length of the front lens unit, EA is an effective diameter of a lens surface closest to the image side in the rear lens unit, fL2 is a focal length of a second partial unit consisting of all lenses disposed on the image side of the aperture stop in the front lens unit, Dair is a thickness of the biconvex air lens on an optical axis, and L is a distance from a lens surface closest to the image side to a lens surface closest to the object side in the optical system.