Optical system, optical apparatus equipped therewith, and method for manufacturing optical system
AssigneeNikon Corporation
InventorsHiroki HARADA, Issei TANAKA
Life of this patent
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Abstract
An optical system SL installed in a single-lens reflex camera includes, in order from an object side, a first lens group G1, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power. The second lens group G2 is disposed movably in a direction including a component perpendicular to an optical axis, and a given conditional expression is satisfied, thereby providing an optical system having excellent optical performance with excellent vibration reduction performance, an optical apparatus equipped with the optical system, and a method for manufacturing the optical system.
Claims58
An optical system comprising, in order from an object side:
- a first lens group;
- a second lens group having negative refractive power;
- and
- a third lens group having positive refractive power,
- the second lens group being disposed movably in a direction including a component perpendicular to an optical axis, and
- the following conditional expression being satisfied:
- 0.30<f/f23<0.95
- where f denotes a focal length of the optical system upon focusing on an infinitely distant object, and f23 denotes a combined focal length of the second lens group and the third lens group upon focusing on an infinitely distant object.
An optical system comprising:
- a first lens group;
- a second lens group having negative refractive power, disposed to an image side of the first lens group movably in a direction including a component perpendicular to an optical axis;
- a third lens group having positive refractive power, disposed to the image side of the second lens group;
- and
- an aperture stop disposed to the image side of the second lens group,
- the second lens group including a positive lens with a convex surface facing an object side.
An optical system comprising, in order from an object side:
- a first lens group;
- a second lens group having negative refractive power;
- and
- a third lens group having positive refractive power,
- the second lens group being disposed movably in a direction including a component perpendicular to an optical axis, and
- the following conditional expression being satisfied:
- 2.00<Σdvr/f<5.00
- where Σdvr denotes a distance between the most image side lens surface of the second lens group and the paraxial focal plane of the optical system upon focusing on an infinitely distant object, and f denotes a focal length of the optical system upon focusing on an infinitely distant object.
A method for manufacturing an optical system including, in order from an object side, a first lens group, a second lens group having negative refractive power, and a third lens group having positive refractive power, the method comprising steps of:
- disposing the second lens group movably in a direction including a component perpendicular to an optical axis;
- and
- disposing each lens group with satisfying the following conditional expression:
- 0.30<f/f23<0.95
- where f denotes a focal length of the whole of the optical system upon focusing on an infinitely distant object, and f23 denotes a combined focal length of the second lens group and the third lens group upon focusing on an infinitely distant object.
A method for manufacturing an optical system comprising steps of:
- disposing a first lens group;
- disposing a second lens group having negative refractive power to an image side of the first lens group movably in a direction including a component perpendicular to an optical axis;
- disposing a third lens group having positive refractive power to the image side of the second lens group;
- disposing an aperture stop to the image side of the second lens group;
- and
- disposing the second lens group including a positive lens with a convex surface facing an object side.
A method for manufacturing an optical system including, in order from an object side, a first lens group, a second lens group having negative refractive power, and a third lens group having positive refractive power, the method comprising steps of:
- disposing the second lens group movably in a direction including a component perpendicular to an optical axis;
- disposing each lens group with satisfying the following conditional expression:
- 2.00<Σdvr/f<5.00
- where Σdvr denotes a distance between the most image side lens surface of the second lens group and the paraxial focal plane of the optical system upon focusing on an infinitely distant object, and f denotes a focal length of the optical system upon focusing on an infinitely distant object.
Dependencies are inferred from the claim text.