US 12,449,646 B2
Optical system and image pickup apparatus having the same
Takeharu Nakada, Tochigi (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Dec. 29, 2022, as Appl. No. 18/148,349.
Claims priority of application No. 2022-000018 (JP), filed on Jan. 1, 2022.
Prior Publication US 2023/0213745 A1, Jul. 6, 2023
Int. Cl. G02B 15/22 (2006.01); G02B 13/02 (2006.01); G02B 15/14 (2006.01)
CPC G02B 15/22 (2013.01) [G02B 13/02 (2013.01); G02B 15/143105 (2019.08)] 21 Claims
OG exemplary drawing
 
1. An optical system comprising, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a third lens unit having positive refractive power,
wherein each distance between adjacent lens units changes during focusing,
wherein during focusing from an infinity object to the closest object, the first and third lens units do not move and the second lens unit moves toward the image side,
wherein the third lens unit consists of, in order from the object side to the image side, a first subunit having positive refractive power, a second subunit having negative refractive power, and a third subunit having positive refractive power,
wherein the second subunit moves in a direction including a component in a direction orthogonal to an optical axis during image stabilization,
wherein the second subunit includes a positive lens and a negative lens, and
wherein the following inequalities are satisfied:
1.90<N3b_ave
f3b/f<−0.25
2.5<LDis/BF<6.5
where N3b_ave is an average value of refractive indices of all lenses included in the second subunit, f3b is a focal length of the second subunit, f is a focal length of the optical system, LDis is a distance on the axis from a lens surface closest to an object in the second subunit to an image plane, and BF is a distance on the axis from a lens surface closest to the image plane of the system to the image plane.