Zoom lens, optical apparatus, and method for manufacturing zoom lens
AssigneeNikon Corporation
InventorTakeshi Umeda
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; a fourth lens group; and a fifth lens group. When the zoom lens performs varying magnification, the distance between the first and second lens groups changes, the distance between the second and third lens groups changes, the distance between the third and fourth lens groups changes, the distance between the fourth and fifth lens groups changes, the second and fourth lens groups move along the same trajectory along the optical axis, and at least the third lens group moves along the optical axis.
Claims7
A zoom lens comprising, in order from an object along an optical axis:
- a first lens group having a negative refractive power;
- a second lens group having a positive refractive power;
- a third lens group having a negative refractive power;
- and
- a fourth lens group, wherein
- when the zoom lens performs zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis, a distance between the first and second lens groups changes, a distance between the second and third lens groups changes, and a distance between the third and fourth lens groups changes,
- the first lens group comprises, in order from the object along the optical axis, a negative lens, a negative lens, a negative lens, and a positive lens,
- the third lens group consists of one lens component having negative refractive power, and
- the following conditional expression is satisfied:
- 1.500<(−f3)/fw<7.000
- where
- f3:
- a focal length of the third lens group,
- fw:
- a focal length of the zoom lens in a wide-angle end state.
A method for manufacturing a zoom lens, wherein
- the zoom lens includes, in order from an object along an optical axis:
- a first lens group having a negative refractive power;
- a second lens group having a positive refractive power;
- a third lens group having a negative refractive power;
- and a fourth lens group,
- the method comprising:
- arranging the lens groups such that when the zoom lens performs zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis, a distance between the first and second lens groups changes, a distance between the second and third lens groups changes, and a distance between the third and fourth lens groups changes;
- configuring the first lens group to comprise, in order from the object along the optical axis, a negative lens, a negative lens, a negative lens, and a positive lens;
- configuring the third lens group to consist of one lens component having negative refractive power;
- and
- satisfying the following conditional expression:
- 1.500<(−f3)/fw<7.000
- where
- f3:
- a focal length of the third lens group,
- fw:
- a focal length of the zoom lens in a wide-angle end state.
Dependencies are inferred from the claim text.