Zoom lens and image pickup apparatus
A zoom lens includes, in order from an object side to an image side, a first positive lens unit fixed for zooming, a second negative lens unit that moves during zooming, at least two lens units that move during zooming, a final positive lens unit disposed closest to an image plane and fixed for zooming, and an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end. The first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing. Predetermined inequalities are satisfied.
1 . A zoom lens comprising, in order from an object side to an image side:
a first lens unit having positive refractive power and fixed for zooming;
a second lens unit having negative refractive power and configured to move during zooming;
at least two lens units configured to move during zooming;
a final lens unit having positive refractive power, disposed closest to an image plane, and fixed for zooming; and
an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end,
wherein the first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing,
wherein the second lens unit includes a first negative lens closest to the object in the second lens unit, at least one negative lens other than the first negative lens, and at least one positive lens, and
wherein the following inequalities are satisfied:
6
0
≤
v
d
2
1
≤
105
30
≤
vd
2
Nave
≤
65
1.5
≤
f
21
/
f
2
≤
5
.
0
where νd21 is an Abbe number of a material of the first negative lens based on d-line, νd2Nave is an average Abbe number of a material of the at least one negative lens other than the first negative lens in the second lens unit, and f21 is a focal length of the first negative lens, and f2 is a focal length of the second lens unit.
2 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
0
<
θ
g
F
2
1
+
0
.
0
0
1
×
vd
21
-
0.603
where θgF21 is a partial dispersion ratio for g-line and F-line of the material of the first negative lens.
3 . The zoom lens according to claim 1 , wherein the second lens unit includes at least three negative lenses including the first negative lens.
4 . The zoom lens according to claim 1 , wherein the first negative lens is a single lens.
5 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
vd
2
P
min
≤
2
8
where νd2Pmin is a minimum Abbe number among Abbe numbers based on the d-line of a material of the at least one positive lens of the second lens unit.
6 . The zoom lens according to claim 1 , wherein the first lens unit includes, in order from the object side to the image side, a first sub-lens unit fixed for focusing, a second sub-lens unit configured to move for focusing, and a third sub-lens unit fixed for focusing.
7 . A zoom lens comprising, in order from an object side to an image side:
a first lens unit having positive refractive power and fixed for zooming;
a second lens unit having negative refractive power and configured to move during zooming;
at least two lens units configured to move during zooming;
a final lens unit having positive refractive power, disposed closest to an image plane, and fixed for zooming; and
an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end,
wherein the first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing,
wherein the second lens unit includes a first negative lens closest to the object in the second lens unit, at least one negative lens other than the first negative lens, and at least one positive lens,
wherein the at least two lens units configured to move during zooming include, in order from the object side to the image side, a third lens unit having negative refractive power, and at least one lens unit, and
wherein the following inequalities are satisfied:
6
0
≤
v
d
2
1
≤
105
30
≤
vd
2
Nave
≤
65
where νd21 is an Abbe number of a material of the first negative lens based on d-line, and νd2Nave is an average Abbe number of a material of the at least one negative lens other than the first negative lens in the second lens unit.
8 . A zoom lens comprising, in order from an object side to an image side:
a first lens unit having positive refractive power and fixed for zooming;
a second lens unit having negative refractive power and configured to move during zooming;
at least two lens units configured to move during zooming;
a final lens unit having positive refractive power, disposed closest to an image plane, and fixed for zooming; and
an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end,
wherein the first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing,
wherein the second lens unit includes a first negative lens closest to the object in the second lens unit, at least one negative lens other than the first negative lens, and at least one positive lens,
wherein the at least two lens units configured to move during zooming include, in order from the object side to the image side, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power, and
wherein the following inequalities are satisfied:
6
0
≤
v
d
2
1
≤
105
30
≤
vd
2
Nave
≤
65
where νd21 is an Abbe number of a material of the first negative lens based on d-line, and νd2Nave is an average Abbe number of a material of the at least one negative lens other than the first negative lens in the second lens unit.
9 . A zoom lens comprising, in order from an object side to an image side:
a first lens unit having positive refractive power and fixed for zooming;
a second lens unit having negative refractive power and configured to move during zooming;
at least two lens units configured to move during zooming;
a final lens unit having positive refractive power, disposed closest to an image plane, and fixed for zooming; and
an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end,
wherein the first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing,
wherein the second lens unit includes a first negative lens closest to the object in the second lens unit, at least one negative lens other than the first negative lens, and at least one positive lens,
wherein the final lens unit is a fifth lens unit counted from the object side, and
wherein the following inequalities are satisfied:
6
0
≤
v
d
2
1
≤
105
30
≤
vd
2
Nave
≤
65
where νd21 is an Abbe number of a material of the first negative lens based on d-line, and νd2Nave is an average Abbe number of a material of the at least one negative lens other than the first negative lens in the second lens unit.
10 . An image pickup apparatus comprising:
a zoom lens; and
an image sensor configured to capture an image formed through the zoom lens,
wherein a zoom lens includes, in order from an object side to an image side:
a first lens unit having positive refractive power and fixed for zooming;
a second lens unit having negative refractive power and configured to move during zooming;
at least two lens units configured to move during zooming;
a final lens unit having positive refractive power, disposed closest to an image plane, and fixed for zooming; and
an aperture stop disposed between a lens surface closest to the image plane of the second lens unit and a lens surface closest to an object of the final lens unit, configured to move during zooming, and located closer to the image plane at a telephoto end than at a wide-angle end,
wherein the first lens unit includes a sub-lens unit disposed closest to the object in the first lens unit and fixed for focusing, and a sub-lens unit configured to move for focusing,
wherein the second lens unit includes a first negative lens closest to the object in the second lens unit, at least one negative lens other than the first negative lens, and at least one positive lens, and
wherein the following inequalities are satisfied:
6
0
≤
v
d
2
1
≤
105
30
≤
vd
2
Nave
≤
65
1.5
≤
f
21
/
f
2
≤
5
.
0
where νd21 is an Abbe number of a material of the first negative lens based on d-line, νd2Nave is an average Abbe number of a material of the at least one negative lens other than the first negative lens in the second lens unit, and f21 is a focal length of the first negative lens, and f2 is a focal length of the second lens unit.