Zoom lens, optical apparatus, and method for manufacturing zoom lens
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.
1. 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;
a fourth lens group; and
a fifth lens group, wherein
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, and
the following conditional expressions are satisfied:
2.100<(− f 3)/ fw< 10.000
0.050<| m 34|/ fw< 1.250
where
f3: a focal length of the third lens group,
fw: a focal length of the zoom lens in the wide-angle end state, and
m34: a change in distance between the third lens group and the fourth lens group along the optical axis upon zooming from the wide-angle end state to a telephoto end state.
2. The zoom lens according to claim 1 , wherein
the fourth lens group has a positive refractive power, and
the fifth lens group has a positive refractive power.
3. The zoom lens according to claim 1 , wherein
the following conditional expression is satisfied:
1.000< f 5/(− f 1)<10.000
where
f5: a focal length of the fifth lens group,
f1: a focal length of the first lens group.
4. The zoom lens according to claim 1 , wherein
the following conditional expression is satisfied:
0.300<| m 12|/ fw< 5.000
where
m12: a change in distance between the first lens group and the second lens group along the optical axis upon zooming from the wide-angle end state to the telephoto end state,
fw: a focal length of the zoom lens in the wide-angle end state.
5. The zoom lens according to claim 1 , wherein
the following conditional expression is satisfied:
0.200< f 5/ f 4<4.000
where
f5: a focal length of the fifth lens group,
f4: a focal length of the fourth lens group.
6. The zoom lens according to claim 1 , wherein
the following conditional expression is satisfied:
0.500< f 4/ f 2<10.000
where
f4: a focal length of the fourth lens group,
f2: a focal length of the second lens group.
7. The zoom lens according to claim 1 , wherein
the fifth lens group has a meniscus-shaped positive lens having a convex surface oriented toward the image side, and
the following conditional expression is satisfied:
1.100<( r 1+ r 2)/( r 1− r 2)<5.000
where
r1: a radius of curvature of an object-side surface of the positive lens,
r2: a radius of curvature of an image-side surface of the positive lens.
8. The zoom lens according to claim 1 , wherein
at least one lens of the third lens group is configured to be movable so as to include a component in a direction orthogonal to the optical axis.
9. The zoom lens according to claim 1 , wherein
at least one lens of the second lens group is configured to be movable so as to include a component in a direction orthogonal to the optical axis.
10. The zoom lens according to claim 1 , wherein
at least one lens of the fourth lens group is configured to be movable so as to include a component in a direction orthogonal to the optical axis.
11. The zoom lens according to claim 1 , wherein
the zoom lens performs focusing from an object at infinity to an object at a close distance by moving at least one lens of the second lens group along the optical axis.
12. The zoom lens according to claim 1 , wherein
the zoom lens performs focusing from an object at infinity to an object at a close distance by moving at least one lens of the third lens group along the optical axis.
13. The zoom lens according to claim 1 , wherein
the zoom lens performs focusing from an object at infinity to an object at a close distance by moving at least one lens of the fourth lens group along the optical axis.
14. The zoom lens according to claim 1 , wherein
the zoom lens performs focusing from an object at infinity to an object at a close distance by moving a portion of the fifth lens group or the entire fifth lens group along the optical axis.
15. The zoom lens according to claim 1 , wherein
an aperture stop is provided between the second lens group and the third lens group.
16. An optical apparatus having the zoom lens of claim 1 .
17. 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; a fourth lens group; and a fifth lens group, wherein
the method includes:
arranging the zoom lens such that, 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, and
satisfying the following conditional expressions:
2.100<(− f 3)/ fw< 10.000
0.050<| m 34|/ fw< 1.250
where
f3: a focal length of the third lens group,
fw: a focal length of the zoom lens in the wide-angle end state, and
m34: a change in distance between the third lens group and the fourth lens group along the optical axis upon zooming from the wide-angle end state to a telephoto end state.