US 2003/0072088 A1 · Zoom lens system

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.

Claims20

Dependent claims

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.

9 more elements

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 fixed stop being arranged between the first lens group and the second lens group;
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;
when the state of lens group positions varies from the wide-angle end state to a certain intermediate focal length state, a distance between the first lens group and the fixed stop decreasing as the fixed stop is moved with the second lens group in a body;
and
when the state of lens group positions varies from the certain intermediate focal length state to the telephoto end state, a distance between the second lens group and the fixed stop decreasing as the fixed stop is moved with the first lens group in a body.

5 more elements

Dependencies are inferred from the claim text.

Zoom lens system

Life of this patent

Zoom lens system

Life of this patent

Abstract

Claims20