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US 2019/0162939 A1Published application
Optical system and image capturing apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorsShinichiro Saito, Makoto Nakahara, Suguru Inoue, Akira Mizuma, Masakazu Yamagishi
Life of this patent
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Abstract
An optical system is constituted of a first lens unit having a positive refractive power, a second lens unit having a positive refractive power and moving when focusing is performed, and a third lens unit which are arranged in this order from an object side to an image side, and distances between neighboring lens units are changed when focusing is performed. In the optical system, a back focus, arrangement of the second lens unit, and the like are appropriately set.
Claims16
An optical system comprising:
- a first lens unit having a positive refractive power, a second lens unit having a positive refractive power, and a third lens unit which are arranged in order from an object side to an image side,
- wherein the second lens unit moves in focusing, thereby changing a distance between adjacent lens units,
- wherein the first lens unit includes a positive lens G1 arranged closest to the object side in the optical system, and
- wherein the following conditional expressions are satisfied:
- LD/f<1.00,
- 0.15<L/f<0.48, and
- 0.02<BF/fG1<0.14,
- where LD is a distance on an optical axis between a lens surface of the optical system closest to the object side and an image plane, L is a distance on the optical axis between a lens surface in the second lens unit closest to the object side and the image plane when focusing on an object at infinity, f is a focal length of the optical system, BF is a back focus of the optical system, and fG1 is a focal length of the positive lens G1.
5 more elements
An image capturing apparatus comprising:
- an optical system and an image pickup element configured to receive light of an image formed by the optical system,
- wherein the optical system includes a first lens unit having a positive refractive power, a second lens unit having a positive refractive power, and a third lens unit which are arranged in this order from an object side to an image side,
- wherein the second lens unit moves in focusing, thereby changing a distance between adjacent lens units,
- wherein the first lens unit includes a positive lens G1 arranged closest to the object side in the optical system, and
- wherein the following conditional expressions are satisfied:
- LD/f<1.00,
- 0.15<L/f<0.48, and
- 0.02<BF/fG1<0.14,
- where LD is a distance on an optical axis between a lens surface of the optical system closest to the object side and an image plane, L is a distance on the optical axis between a lens surface in the second lens unit closest to the object side and the image plane when focusing on an object at infinity, f is a focal length of the optical system, BF is a back focus of the optical system, and fG1 is a focal length of the positive lens G1.
6 more elements
Dependencies are inferred from the claim text.