ZOOM LENS AND IMAGE CAPTURING APPARATUS
First Claim
Patent Images
1. A zoom lens comprising:
- in order from an object side to an image side,a first lens group having negative refractive power;
a second lens group having positive refractive power;
a third lens group having positive refractive power; and
a fourth lens group having positive refractive power,wherein, in zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens,wherein the third lens group includes a single lens or a single cemented lens, andwherein the following conditional expressions (a) and (b) are satisfied,
Δ
m3/(fw×
ft)1/2<
0.2
conditional expression (a);
d23_max/(fw×
ft)1/2<
0.4
conditional expression (b);
whereΔ
m3;
a variation amount of a distance between the second lens group and the third lens group in varying magnification,d23_max;
a maximum value of the distance between the second lens group and the third lens group in varying magnification,fw;
a system focal length at the wide-angle end, andft;
a system focal length at the telescopic end.
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Abstract
There is provided a zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. In zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens. The third lens group includes a single lens or a single cemented lens.
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Citations
8 Claims
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1. A zoom lens comprising:
- in order from an object side to an image side,
a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, wherein, in zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens, wherein the third lens group includes a single lens or a single cemented lens, and wherein the following conditional expressions (a) and (b) are satisfied,
Δ
m3/(fw×
ft)1/2<
0.2
conditional expression (a);
d23_max/(fw×
ft)1/2<
0.4
conditional expression (b);where Δ
m3;
a variation amount of a distance between the second lens group and the third lens group in varying magnification,d23_max;
a maximum value of the distance between the second lens group and the third lens group in varying magnification,fw;
a system focal length at the wide-angle end, andft;
a system focal length at the telescopic end. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- in order from an object side to an image side,
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8. An image capturing apparatus comprising:
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a zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power; and an image sensor converting an optical image formed by the zoom lens into an electric signal, wherein, in zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens, wherein the third lens group includes a single lens or a single cemented lens, and wherein the following conditional expressions (a) and (b) are satisfied,
Δ
m3/(fw×
ft)1/2<
0.2
conditional expression (a);
d23_max/(fw×
ft)1/2<
0.4
conditional expression (b);where Δ
m3;
a variation amount of a distance between the second lens group and the third lens group in varying magnification,d23_max;
a maximum value of the distance between the second lens group and the third lens group in varying magnification,fw;
a system focal length at the wide-angle end, andft;
a system focal length at the telescopic end.
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Specification