Zoom lens and image-capturing apparatus
A zoom lens consists of four or more lens units including, in order from an object side to an image side, first, second, and third lens units having positive, negative, and positive refractive powers, respectively. During zooming from a wide-angle end to a telephoto end, the first lens unit moves, a distance between the first lens unit and the second lens unit is widened, and a distance between the second lens unit and the third lens unit is narrowed. The first lens unit consists of a single positive lens, the second lens unit includes three single lens elements, each having a negative refractive power, arranged continuously in order from the object side to the image side, predetermined conditions are satisfied.
1. A zoom lens consisting of four or more lens units including, 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, and a third lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit moves, a distance between the first lens unit and the second lens unit is widened, and a distance between the second lens unit and the third lens unit is narrowed,
wherein the first lens unit consists of a single positive lens,
wherein the second lens unit includes three single lens elements, each having a negative refractive power, arranged continuously in order from the object side to the image side, and
wherein following inequalities are satisfied:
1.715< SFY< 10.0, and
−7.5< f 1/ f 2<−0.5,
where SFY is a shape factor of a second single lens element adjacent to a first single lens element arranged on a most object side among the three single lens elements, f1 is a focal length of the first lens unit, and f2 is a focal length of the second lens unit.
2. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
1.0< SFX< 3.0,
where SFX is a shape factor of the first single lens element.
3. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.6< SF 1<3.0,
where SF1 is a shape factor of the single positive lens of the first lens unit.
4. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
1.19< nX/nZ< 1.31,
where nX is a refractive index for a d-line of the first single lens element arranged on the most object side among the three single lens elements and nZ is a refractive index for the d-line of a third single lens element arranged on a most image side among the three single lens elements.
5. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.35< fX/fY< 1.50,
where fX is a focal length of the first single lens element, and fY is a focal length of the second single lens element.
6. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.70< fX/f 2<2.20,
where fX is a focal length of the first single lens element.
7. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.90< skw/fw< 1.45,
where fw is a focal length of the zoom lens at the wide-angle end, and skw is a back focus of the zoom lens at the wide-angle end.
8. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
5.1< f 1/ fw< 14.0,
where fw is a focal length of the zoom lens at the wide-angle end.
9. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.38< f 3/ ft< 2.00,
where f3 is a focal length of the third lens unit, and ft is a focal length of the zoom lens at the telephoto end.
10. The zoom lens according to claim 1 ,
wherein a following inequality is satisfied:
0.3< V< 1.0,
where V is a third-order aberration coefficient of distortion at the wide-angle end.
11. The zoom lens according to claim 1 ,
wherein the zoom lens consists of, in order from the object side to the image side, the first lens unit, the second lens unit, the third lens unit, and a rear group composed of one or more lens units,
wherein the rear group includes, in order from the object side to the image side, a fourth lens unit having a negative refractive power, a fifth lens unit having a positive refractive power, and a sixth lens unit.
12. The zoom lens according to claim 1 ,
wherein the zoom lens consists of, in order from the object side to the image side, the first lens unit, the second lens unit, the third lens unit, and a rear group composed of one or more lens units,
wherein the rear group includes, in order from the object side to the image side, a fourth lens unit having a positive refractive power, a fifth lens unit having a negative refractive power, and a sixth lens unit.
13. A zoom lens consisting of four or more lens units including, 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, and a third lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit moves, a distance between the first lens unit and the second lens unit is widened, and a distance between the second lens unit and the third lens unit is narrowed,
wherein the first lens unit consists of one element lens having a positive refractive power,
wherein the second lens unit includes three single lens elements, each having a negative refractive power, arranged continuously in order from the object side to the image side, and
wherein following inequalities are satisfied:
1.715< SFY< 10.0,
−7.5< f 1/ f 2<−0.5, and
0.5< fZ/f 2<1.96,
where SFY is a shape factor of a second single lens element adjacent to a first single lens element arranged on a most object side among the three single lens elements, f1 is a focal length of the first lens unit, f2 is a focal length of the second lens unit, fZ is a focal length of a third single lens element arranged on a most image side among the three single lens elements.
14. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
1.0< SFX< 3.0,
where SFX is a shape factor of the first single lens element.
15. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
0.6< SF 1<3.0,
where SF1 is a shape factor of the one element lens having the positive refractive power of the first lens unit.
16. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
1.19< nX/nZ< 1.31,
where nX is a refractive index for a d-line of the first single lens element arranged on the most object side among the three single lens elements and nZ is a refractive index for the d-line of the third single lens element arranged on the most image side among the three single lens elements.
17. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
0.35< fX/fY< 1.50,
where fX is a focal length of the first single lens element, and fY is a focal length of the second single lens element.
18. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
0.70< fX/f 2<2.20,
where fX is a focal length of the first single lens element.
19. The zoom lens according to claim 13 ,
wherein a following inequality is satisfied:
0.90< skw/fw< 1.45,
where fw is a focal length of the zoom lens at the wide-angle end, and skw is a back focus of the zoom lens at the wide-angle end.
20. An image-capturing apparatus comprising:
a zoom lens; and
an image sensor configured to receive an image formed by the zoom lens,
wherein the zoom lens consists of four or more lens units including, 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, and a third lens unit having a positive refractive power,
wherein during zooming from a wide-angle end to a telephoto end, the first lens unit moves, a distance between the first lens unit and the second lens unit is widened, and a distance between the second lens unit and the third lens unit is narrowed,
wherein the first lens unit consists of a single positive lens,
wherein the second lens unit includes three single lens elements, each having a negative refractive power, arranged continuously in order from the object side to the image side, and
wherein following inequalities are satisfied:
1.715< SFY< 10.0, and
−7.5< f 1/ f 2<−0.5,
where SFY is a shape factor of a second single lens element adjacent to a first single lens element arranged on a most object side among the three single lens elements, f1 is a focal length of the first lens unit, and f2 is a focal length of the second lens unit.