Zoom lens system
First Claim
1. A zoom lens system comprising, in order from an object along an optical axis:
- a first lens group having negative refractive power; and
a second lens group having positive refractive power;
a distance between the first lens group and the second lens group decreasing when the state of lens group positions varies from a wide-angle end state to a telephoto end state;
the second lens group being composed of, in order from the object;
a first lens having positive refractive power;
a first cemented lens having negative refractive power; and
a second cemented lens having positive refractive power;
the first cemented lens in the second lens group being constructed by a positive lens cemented with a negative lens; and
the second cemented lens in the second lens group being constructed by a negative lens cemented with a positive lens.
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Abstract
According to one aspect of the present invention, a zoom lens system includes, in order from an object along an optical axis, a first lens group having negative refractive power, and a second lens group having positive refractive power. A distance between the first lens group and the second lens group decreases when the state of lens group positions varies from a wide-angle end state to a telephoto end state. The second lens group is composed of, in order from the object, a first lens having positive refractive power, a first cemented lens having negative refractive power, and a second cemented lens having positive refractive power. The first cemented lens in the second lens group is constructed by a positive lens cemented with a negative lens. The second cemented lens in the second lens group is constructed by a negative lens cemented with a positive lens.
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Citations
16 Claims
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1. A zoom lens system comprising, in order from an object along an optical axis:
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a first lens group having negative refractive power; and
a second lens group having positive refractive power;
a distance between the first lens group and the second lens group decreasing when the state of lens group positions varies from a wide-angle end state to a telephoto end state;
the second lens group being composed of, in order from the object;
a first lens having positive refractive power;
a first cemented lens having negative refractive power; and
a second cemented lens having positive refractive power;
the first cemented lens in the second lens group being constructed by a positive lens cemented with a negative lens; and
the second cemented lens in the second lens group being constructed by a negative lens cemented with a positive lens. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification