Zoom lens and image pickup apparatus
A zoom lens includes a first lens unit having negative refractive power and disposed closest to an object, and a rear group including three or more lens units and disposed on an image side of the first lens unit. A distance between adjacent lens units changes during zooming. The first lens unit moves toward the image side during zooming from a wide-angle end to a telephoto end. Predetermined inequalities are satisfied.
1 . A zoom lens comprising:
a first lens unit having negative refractive power and disposed closest to an object; and
a rear group including three or more lens units and disposed on an image side of the first lens unit,
wherein a distance between adjacent lens units changes during zooming,
wherein the first lens unit moves toward the image side during zooming from a wide-angle end to a telephoto end, and
wherein in a case where a sign of a moving amount of a lens unit configured to move toward the image side during zooming from the wide-angle end to the telephoto end is set positive, the following inequalities are satisfied:
0.3
≤
ML
1
/
TLt
≤
0.9
-
0
.
8
0
≤
fL
1
/
ft
≤
-
0.4
where ML1 is a moving amount of the first lens unit during zooming from the wide-angle end to the telephoto end, TLt is an overall optical length of the zoom lens at the telephoto end, fL1 is a focal length of the first lens unit, and ft is a focal length of the zoom lens at the telephoto end.
2 . The zoom lens according to claim 1 , further comprising an aperture stop and an auxiliary aperture, each of which is disposed on the image side of the first lens unit L1.
3 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
-
3.
≤
ML
1
/
fL
1
≤
-
1.
.
4 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
0.1
≤
Skw
/
ML
1
≤
0.6
where Skw is a back focus of the zoom lens at the wide-angle end.
5 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
0
.
1
0
≤
Skt
/
ML
1
≤
0.7
where Skt is a back focus of the zoom lens at the telephoto end.
6 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
0.
2
0
≤
TDL
1
/
ML
1
≤
0
.
6
5
where TDL1 is a distance on an optical axis from a lens surface closest to the object of the first lens unit to a lens surface closest to an image plane of the first lens unit.
7 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
-
0
.
7
0
≤
MLR
1
/
ML
1
≤
-
0
.
0
2
where MLR1 is a moving amount toward an object side of a lens unit closest to the object of the rear group during zooming from the wide-angle end to the telephoto end.
8 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
-
0
.
7
0
≤
MLR
1
/
ft
≤
-
0
.
0
2
where MLR1 is a moving amount of a lens unit closest to the object of the rear group toward an object side during zooming from the wide-angle end to the telephoto end.
9 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
1.
50
≤
ndG
1
≤
2.
where ndG1 is a refractive index for d-line of a lens closest to the object in the zoom lens.
10 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
0.6
≤
fG
1
/
fL
1
≤
2.
where fG1 is a focal length of a lens closest to the object in the zoom lens.
11 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
3.
3
0
≤
β
LRt
/
β
LRw
≤
8.
where βLRt is a lateral magnification of the rear group at the telephoto end, and βLRw is a lateral magnification of the rear group at the wide-angle end.
12 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
-
1.6
≤
Ymax_w
/
fL
1
≤
-
0.2
where Ymax_w is a maximum image height of the zoom lens at the wide-angle end in an in-focus state on an object at infinity.
13 . The zoom lens according to claim 1 , wherein the following inequality is satisfied:
-
2
0
.
0
≤
Dist_w
≤
-
8.
where Dist_w is a distortion amount at a maximum image height of the zoom lens at the wide-angle end in an in-focus state on an object at infinity.
14 . The zoom lens according to claim 1 , wherein the first lens unit includes two or more negative lenses and one or more positive lenses.
15 . The zoom lens according to claim 1 , wherein the rear group includes:
an aperture stop; and
at least one focus lens unit configured to move during focusing, and disposed on the image side of the aperture stop.
16 . The zoom lens according to claim 1 , wherein the rear group includes:
an aperture stop; and
an image stabilizing unit configured to move relative to an optical axis to reduce image blur, and disposed as at least a part of a single lens unit disposed on the image side of the aperture stop.
17 . The zoom lens according to claim 1 , wherein the rear group includes three or more lens units in which distances change during zooming.
18 . The zoom lens according to claim 1 , wherein the three or more lens units included in the rear group include, in order from an object side to the image side:
a second lens unit having positive refractive power;
a third lens unit having negative refractive power;
a fourth lens unit having positive refractive power;
a fifth lens unit having negative refractive power;
a sixth lens unit having negative refractive power; and
a seventh lens unit having positive refractive power.
19 . The zoom lens according to claim 1 , wherein the three or more lens units included in the rear group include, in order from an object side to the image side:
a second lens unit having positive refractive power;
a third lens unit having negative refractive power;
a fourth lens unit having positive refractive power; and
a fifth lens unit having negative refractive power.
20 . The zoom lens according to claim 1 , wherein the three or more lens units included in the rear group include, in order from an object side to the image side:
a second lens unit having negative refractive power;
a third lens unit having positive refractive power;
a fourth lens unit having negative refractive power;
a fifth lens unit having positive refractive power;
a sixth lens unit having negative refractive power; and
a seventh lens unit having positive refractive power.
21 . The zoom lens according to claim 1 , wherein the three or more lens units included in the rear group include, in order from an object side to the image side:
a second lens unit having positive refractive power;
a third lens unit having negative refractive power;
a fourth lens unit having positive refractive power;
a fifth lens unit having negative refractive power; and
a sixth lens unit having positive refractive power.
22 . The zoom lens according to claim 1 , wherein the three or more lens units included in the rear group include, in order from an object side to the image side:
a second lens unit having positive refractive power;
a third lens unit having positive refractive power;
a fourth lens unit having negative refractive power;
a fifth lens unit having positive refractive power;
a sixth lens unit having negative refractive power;
a seventh lens unit having positive refractive power; and
an eighth lens unit having positive refractive power.
23 . An image pickup apparatus comprising:
a zoom lens; and
an image sensor configured to capture an optical image formed by the zoom lens,
wherein the zoom lens includes:
a first lens unit having negative refractive power and disposed closest to an object; and
a rear group including three or more lens units and disposed on an image side of the first lens unit,
wherein a distance between adjacent lens units changes during zooming,
wherein the first lens unit moves toward the image side during zooming from a wide-angle end to a telephoto end, and
wherein in a case where a sign of a moving amount of a lens unit configured to move toward the image side during zooming from the wide-angle end to the telephoto end is set positive, the following inequalities are satisfied:
0.3
≤
ML
1
/
TLt
≤
0.9
-
0
.
8
0
≤
fL
1
/
ft
≤
-
0.4
where ML1 is a moving amount of the first lens unit during zooming from the wide-angle end to the telephoto end, TLt is an overall optical length of the zoom lens at the telephoto end, fL1 is a focal length of the first lens unit, and ft is a focal length of the zoom lens at the telephoto end.
24 . The image pickup apparatus according to claim 23 , wherein an effective image circle diameter at the wide-angle end is smaller than that at the telephoto end.