Optical system and image pickup apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorTakahiro Hatada
Life of this patent
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Abstract
In an optical system including, in order from an object side to an image side: a front unit (LF) having a negative refractive power; an aperture stop; and a rear unit (LR) having a positive refractive power, the front unit (LF) includes a meniscus-shaped negative lens (g1) closest to the object side, and a focal length (fw) of the entire optical system, a focal length (fg1) of the meniscus-shaped negative lens (g1), and a curvature radius (R2) of a lens surface on the image side of the meniscus-shaped negative lens (g1) are appropriately set.
Claims13
An optical system, comprising, in order from an object side to an image side:
- a front unit (LF) having a negative refractive power;
- an aperture stop;
- and
- a rear unit (LR) having a positive refractive power,
- wherein the front unit (LF) comprises a meniscus-shaped negative lens (g1) closest to the object side, and
- wherein the following conditional expressions are satisfied:
- 3.0<|fg1/fw|<6.1
- 1.9<R2/fw<3.0
- where fw denotes a focal length of the entire optical system, fg1 denotes a focal length of the meniscus-shaped negative lens (g1), and R2 denotes a curvature radius of a lens surface on the image side of the meniscus-shaped negative lens (g1).
An image pickup apparatus, comprising:
- an optical system;
- and
- an image sensor configured to receive an image formed by the optical system,
- wherein the optical system comprises, in order from an object side to an image side:
- a front unit (LF) having a negative refractive power;
- an aperture stop;
- and
- a rear unit (LR) having a positive refractive power,
- wherein the front unit (LF) comprises a meniscus-shaped negative lens (g1) closest to the object side, and
- wherein the following conditional expressions are satisfied:
- 3.0<|fg1/fw|<6.1
- 1.9<R2/fw<3.0
- where fw denotes a focal length of the entire optical system, fg1 denotes a focal length of the meniscus-shaped negative lens (g1), and R2 denotes a curvature radius of a lens surface on the image side of the meniscus-shaped negative lens (g1).
Dependencies are inferred from the claim text.