Zoom lens and image pickup apparatus having the same
A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and three or more lens units. A distance between adjacent lens units varies during zooming. A predetermined condition is satisfied.
1. A zoom lens comprising, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and three or more lens units,
wherein a distance between adjacent lens units varies during zooming, and
wherein the following conditional expressions are satisfied:
4.8< m 1· f 1/ skw 2 <15.0
2.45<β2 t/β 2 w< 50.00
where m1 is a moving amount of the first lens unit during zooming from a wide-angle end to a telephoto end, f1 is a focal length of the first lens unit, skw is a backfocus at the wide-angle end, β2t is a lateral magnification of the second lens unit at the telephoto end, and β2w is a lateral magnification of the second lens unit at the wide-angle end.
2. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.05< TD 1/ ft< 0.50
where TD1 is a distance on an optical axis from a lens surface closest to an object to a lens surface closest to an image plane in the first lens unit, and ft is a focal length of the zoom lens at the telephoto end.
3. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−4.0< f 1/ fw<− 1.0
where fw is a focal length of the zoom lens at the wide-angle end.
4. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.8< f 2/ fw< 4.0
where f2 is a focal length of the second lens unit, and fw is a focal length of the zoom lens at the wide-angle end.
5. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.3<| fr|/fw< 20.0
where fr is a focal length of a lens unit closest to an image plane, fw is a focal length of the zoom lens at the wide-angle end.
6. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.5< POw/fw< 3.0
where POw is a distance from an image plane to an exit pupil position at the wide-angle end, and fw is a focal length of the zoom lens at the wide-angle end.
7. The zoom lens according to claim 1 , wherein the first lens includes a negative lens closest to an object, and
wherein the following conditional expression is satisfied:
−3.0<( R 2+ R 1)/( R 2− R 1)<−0.3
where R1 is a radius of curvature of the negative lens on the object side, and R2 is a radius of curvature of the negative lens on the image side.
8. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.2< m 2/ fw< 1.4
where m2 is a moving amount of the second lens unit during zooming from the wide-angle end to the telephoto end, and fw is a focal length of the zoom lens at the wide-angle end.
9. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−3.0< fg 1/ fw<− 0.5
where fg1 is a focal length of a lens closest to an object in the zoom lens, and fw is a focal length of the zoom lens at the wide-angle end.
10. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
3.5 <TTDw/skw< 22.0
where TTDw is an overall length of the zoom lens at the wide-angle end.
11. The zoom lens according to claim 1 , wherein the first lens unit consists of a lens having a negative refractive power and a lens having a positive refractive power arranged in this order from the object side to the image side.
12. The zoom lens according to claim 1 , further comprising a third lens unit moves during focusing.
13. The zoom lens according to claim 1 , wherein the three or more lens units include a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power.
14. The zoom lens according to claim 1 , wherein the three or more lens units include a third lens unit having a positive refractive power, and a fourth lens unit having a negative refractive power.
15. The zoom lens according to claim 1 , wherein the three or more lens units include a third lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, a fifth lens unit having a negative refractive power, and a sixth lens unit having a negative refractive power.
16. The zoom lens according to claim 1 , wherein the three or more lens units include a third lens unit having a negative refractive power, a fourth lens unit having a positive refractive power, a fifth lens unit having a negative refractive power, and a sixth lens unit having a positive refractive power.
17. The zoom lens according to claim 1 , wherein a lens unit closest to an object has a negative refractive power.
18. The zoom lens according to claim 1 , wherein the first lens unit monotonically moves to the image side during zooming from the wide-angle end to the telephoto end.
19. The zoom lens according to claim 1 , wherein at least two of the lens units disposed on the image side of the first lens unit move in the same trajectory during zooming from the wide-angle end to the telephoto end.
20. An image pickup apparatus comprising:
a zoom lens;
An image sensor configured to receive an formed by the zoom lens,
wherein the zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and three or more lens units,
wherein a distance between adjacent lens units varies during zooming, and
wherein the following conditional expressions are satisfied:
4.8< m 1· f 1/ skw 2 <15.0
2.45<β2 t/β 2 w< 50.00
where m1 is a moving amount of the first lens unit during zooming from a wide-angle end to a telephoto end, f1 is a focal length of the first lens unit, skw is a backfocus at the wide-angle end, β2t is a lateral magnification of the second lens unit at the telephoto end, and β2w is a lateral magnification of the second lens unit at the wide-angle end.