Zoom lens and image pickup apparatus with the zoom lens
A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, an aperture stop, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. In the zoom lens, during zooming from a wide-angle end to a telephoto end, the first lens unit is configured to remain stationary, the second lens unit, the third lens unit, and the fourth lens unit are configured to move separately from one another, and the aperture stop is configured to move along a locus convex towards the object side.
1. A zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
an aperture stop;
a third lens unit having a positive refractive power;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit is configured to remain stationary, the second lens unit, the third lens unit, and the fourth lens unit are configured to move separately from one another, and the aperture stop is configured to move along a locus convex towards the object side,
wherein, when f3 is a focal length of the third lens unit and DS3 is an interval between the aperture stop and the third lens unit at a zooming position at which the aperture stop is located closest to the object side, the following condition is satisfied:
0.5 <DS 3 /f 3<2.0.
2. The zoom lens according to claim 1 , wherein the fourth lens unit is configured to move along a locus convex towards the object side to be located at a position closest to the object side at a zooming position at which the aperture stop is located closest to the object side.
3. The zoom lens according to claim 1 , wherein, when f2 is a focal length of the second lens unit and f3 is a focal length of the third lens unit, the following condition is satisfied:
−2.50 <f 3 /f 2<−1.50.
4. The zoom lens according to claim 1 , wherein, when f2 is a focal length of the second lens unit, fw is a focal length of the zoom lens at the wide-angle end, and ft is a focal length of the zoom lens at the telephoto end, the following condition is satisfied:
−1.00 <f 2/( fw×ft ) 1/2 <−0.50.
5. The zoom lens according to claim 1 , wherein, when β2W is a lateral magnification of the second lens unit at the wide-angle end, β2T is a lateral magnification of the second lens unit at the telephoto end, β3W is a lateral magnification of the third lens unit at the wide-angle end, and β3T is a lateral magnification of the third lens unit at the telephoto end, the following condition is satisfied:
0.3<(β2 T /(β2 W )/(β3 T /(β3 W )<3.0.
6. The zoom lens according to claim 1 , wherein, when β3W is a lateral magnification of the third lens unit at the wide-angle end and β3T is a lateral magnification of the third lens unit at the telephoto end, the following condition is satisfied:
1.5<β3 T/β 3 W< 4.5.
7. The zoom lens according to claim 1 , wherein, when νd4 is a dispersion value of a material of one negative lens included in the fourth lens unit, the following condition is satisfied:
50 <νd 4<90.
8. The zoom lens according to claim 1 , wherein the fifth lens unit includes three lenses.
9. A zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
an aperture stop;
a third lens unit having a positive refractive power;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit is configured to remain stationary, the second lens unit, the third lens unit, and the fourth lens unit are configured to move separately from one another, and the aperture stop is configured to move along a locus convex towards the object side,
wherein, when f2 is a focal length of the second lens unit, fw is a focal length of the zoom lens at the wide-angle end, and ft is a focal length of the zoom lens at the telephoto end, the following condition is satisfied:
−1.00 <f 2/( fw×ft ) 1/2 <−0.50.
10. The zoom lens according to claim 9 , wherein the fourth lens unit is configured to move along a locus convex towards the object side to be located at a position closest to the object side at a zooming position at which the aperture stop is located closest to the object side.
11. The zoom lens according to claim 9 , wherein, when f2 is a focal length of the second lens unit and f3 is a focal length of the third lens unit, the following condition is satisfied:
−2.50 <f 3 /f 2<−1.50.
12. The zoom lens according to claim 9 , wherein, when β2W is a lateral magnification of the second lens unit at the wide-angle end, β2T is a lateral magnification of the second lens unit at the telephoto end, β3W is a lateral magnification of the third lens unit at the wide-angle end, and β3T is a lateral magnification of the third lens unit at the telephoto end, the following condition is satisfied:
0.3<(β2 T /(β2 W )/(β3 T /(β3 W )<3.0.
13. The zoom lens according to claim 9 , wherein, when β3W is a lateral magnification of the third lens unit at the wide-angle end and β3T is a lateral magnification of the third lens unit at the telephoto end, the following condition is satisfied:
1.5<β3 T/β 3 W< 4.5.
14. The zoom lens according to claim 9 , wherein, when νd4 is a dispersion value of a material of one negative lens included in the fourth lens unit, the following condition is satisfied:
50 <νd 4<90.
15. The zoom lens according to claim 9 , wherein the fifth lens unit includes three lenses.
16. An image pickup apparatus comprising:
a zoom lens; and
an image sensor configured to receive an image formed by the zoom lens,
wherein the zoom lens comprises, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
an aperture stop;
a third lens unit having a positive refractive power;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive refractive power, and
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit is configured to remain stationary, the second lens unit, the third lens unit, and the fourth lens unit are configured to move separately from one another, and the aperture stop is configured to move along a locus convex towards the object side,
wherein, when f3 is a focal length of the third lens unit and DS3 is an interval between the aperture stop and the third lens unit at a zooming position at which the aperture stop is located closest to the object side, the following condition is satisfied:
0.5 <DS 3 /f 3<2.0.
17. An image pickup apparatus comprising:
a zoom lens; and
an image sensor configured to receive an image formed by the zoom lens,
wherein the zoom lens comprises, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
an aperture stop;
a third lens unit having a positive refractive power;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit is configured to remain stationary, the second lens unit, the third lens unit, and the fourth lens unit are configured to move separately from one another, and the aperture stop is configured to move along a locus convex towards the object side,
wherein, when f2 is a focal length of the second lens unit, fw is a focal length of the zoom lens at the wide-angle end, and ft is a focal length of the zoom lens at the telephoto end, the following condition is satisfied:
−1.00 <f 2/( fw×ft ) 1/2 <−0.50.