Optical system, lens apparatus, and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorTakayoshi Yokoyama
Life of this patent
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Abstract
An optical system includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a first reflective member, a second lens unit including an aperture diaphragm and having a positive refractive power, a second reflective member, and a third lens unit having a positive refractive power. Following inequalities are satisfied: −1.27<(f1/f)/Npr<−0.70 0.60<f2/f3<1.60 where f represents a focal length of the optical system, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, and NPr represents a refractive index of the first reflective member.
Claims14
An optical system comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a first reflective member;
- a second lens unit including an aperture diaphragm and having a positive refractive power;
- a second reflective member;
- and
- a third lens unit having a positive refractive power,
- wherein the first lens unit includes all lenses disposed at the object side of the first reflective member in the optical system,
- wherein the second lens unit includes the aperture stop and all lenses disposed between the first reflective member and the second reflective member in the optical system,
- wherein the third lens unit includes all lenses disposed between the second reflective member and an image plane in the optical system, and
- wherein the following inequalities are satisfied:
- 1.27<(f1/f)/Npr<−0.84
- 0.60<f2/f3<1.60
- 4.80<f2/f<10.50
- where f represents a focal length of the optical system, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, and Npr represents a refractive index of the first reflective member.
A lens apparatus comprising two optical systems of a first optical system and a second optical system,
- wherein each of the first optical system and the second optical system includes, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a first reflective member;
- a second lens unit including an aperture diaphragm and having a positive refractive power;
- a second reflective member;
- and
- a third lens unit having a positive refractive power,
- wherein the first lens unit includes all lenses disposed at the object side of the first reflective member in the optical system,
- wherein the second lens unit includes the aperture stop and all lenses disposed between the first reflective member and the second reflective member in the optical system,
- wherein the third lens unit includes all lenses disposed between the second reflective member and an image plane in the optical system, and
- wherein each of the first and second optical systems satisfies following inequalities:
- −1.27<(f1/f)/Npr<−0.84
- 0.60<f2/f3<1.60
- 3.0<f2/f<10.50
- where, f represents a focal length of the optical system, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, and Npr represents a refractive index of the first reflective member.
An image pickup apparatus comprising:
- a lens apparatus including two optical systems of a first optical system and a second optical system;
- and
- an image sensor configured to capture an optical image formed by each of the two optical systems,
- wherein each of the first optical system and the second optical system includes, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a first reflective member;
- a second lens unit including an aperture diaphragm and having a positive refractive power;
- a second reflective member;
- and
- a third lens unit having a positive refractive power,
- wherein the first lens unit includes all lenses disposed at the object side of the first reflective member in the optical system,
- wherein the second lens unit includes the aperture stop and all lenses disposed between the first reflective member and the second reflective member in the optical system,
- wherein the third lens unit includes all lenses disposed between the second reflective member and an image plane in the optical system, and
- wherein each of the first and second optical systems satisfies following inequalities:
- −1.27<(f1/f)/Npr<−0.84
- 0.60<f2/f3<1.60
- 3.80<f2/f<10.50
- where f represents a focal length of the optical system, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, and Npr represents a refractive index of the first reflective member.
Dependencies are inferred from the claim text.