Abstract: Providing a zoom lens system having a high zoom ratio being compact with high optical performance. The system includes, in order from an object along an optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, at least one lens group having positive refractive power, and an n-th lens group GN being disposed to the most image side. The n-th lens group GN with positive refractive power includes, in order from the object, a front group GNa and a rear group GNb having positive refractive power. Focusing on an object is carried out by moving the rear group GNb along the optical axis, and a given conditional expression is satisfied.

Abstract: Providing a zoom lens system having a high zoom ratio being compact with high optical performance. The system includes, in order from an object along an optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, at least one lens group having positive refractive power, and an n-th lens group GN being disposed to the most image side. The n-th lens group GN with positive refractive power includes, in order from the object, a front group GNa and a rear group GNb having positive refractive power. Focusing on an object is carried out by moving the rear group GNb along the optical axis, and a given conditional expression is satisfied.

Abstract: A zoom lens of the present invention has a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, which are disposed in order from an object, wherein the distances between each lens group are changed upon zooming, the second lens group has at least two positive lenses having an aspherical surface respectively, and when ?d is an Abbe number at least one of the positive lenses having the aspherical surface satisfies a condition of the following expression: ?d>70.

Abstract: Providing a high optical performance zoom lens system with realizing a high zoom ratio and compactness suitable for a highly integrated electronic imaging device. The system includes, in order from an object along an optical axis: a first group G1 having positive refractive power; a second group G2 having negative refractive power; a third group G3 having positive refractive power; a fourth group G4 having positive refractive power; and a fifth group G5 having negative refractive power. Upon zooming from a wide-angle end state W to a telephoto end state T, the second group G2 and the fourth group G4 are moved along the optical axis. The first group G1 includes, in order from the object along the optical axis, a front group G1f having negative refractive power, an optical-path-bending element P for bending an optical path, and a rear group G1r having positive refractive power. Given expression is satisfied.

Abstract: A zoom lens of the present invention has a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, which are disposed in order from an object, wherein the distances between each lens group are changed upon zooming, the second lens group has at least two positive lenses having an aspherical surface respectively, and when ?d is an Abbe number at least one of the positive lenses having the aspherical surface satisfies a condition of the following expression: ?d>70.

Abstract: Providing a high optical performance zoom lens system with realizing a high zoom ratio and compactness suitable for a highly integrated electronic imaging device. The system includes, in order from an object along an optical axis: a first group G1 having positive refractive power; a second group G2 having negative refractive power; a third group G3 having positive refractive power; a fourth group G4 having positive refractive power; and a fifth group G5 having negative refractive power. Upon zooming from a wide-angle end state W to a telephoto end state T, the second group G2 and the fourth group G4 are moved along the optical axis. The first group G1 includes, in order from the object along the optical axis, a front group G1f having negative refractive power, an optical-path-bending element P for bending an optical path, and a rear group G1r having positive refractive power. Given expression is satisfied.

Abstract: Providing a zoom lens system having a high zoom ratio being compact with high optical performance. The system includes, in order from an object along an optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, at least one lens group having positive refractive power, and an n-th lens group GN being disposed to the most image side. The n-th lens group GN with positive refractive power includes, in order from the object, a front group GNa and a rear group GNb having positive refractive power. Focusing on an object is carried out by moving the rear group GNb along the optical axis, and a given conditional expression is satisfied.

Abstract: Providing a compact zoom lens system having high optical performance suitable for an electronic imaging device with a large number of pixels. The zoom lens system includes, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. When zooming from a wide-angle end state to a telephoto end state, the first lens group and the second lens group are moved such that a distance between the first lens group and the second lens group decreases, and a distance between the second lens group and the third lens group increases. The second lens group is composed of at least two positive lens elements and one negative lens element. At least one positive lens element and the negative lens element in the second lens group satisfy given conditional expressions.

Abstract: Providing a compact zoom lens system having high optical performance suitable for an electronic imaging device with a large number of pixels. The zoom lens system includes, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. When zooming from a wide-angle end state to a telephoto end state, the first lens group and the second lens group are moved such that a distance between the first lens group and the second lens group decreases, and a distance between the second lens group and the third lens group increases. The second lens group is composed of at least two positive lens elements and one negative lens element. At least one positive lens element and the negative lens element in the second lens group satisfy given conditional expressions.

Abstract: An eyepiece lens includes first lens group G1 having a negative refracting power including a negative meniscus lens with a concave surface facing eyepoint E.P side, second lens group G2 having a positive refracting power including a lens with both convex surfaces on both ends, and third lens group G3 having a negative refracting power including a negative lens. The first–third lens groups are arranged in an order from eyepoint E.P side, and the eyepiece lens is capable of varying a diopter by moving the second lens group along an optical axis. The eyepiece lens is configured by aspherical surfaces to make the positive refracting power weak while at least one surface of the convex surfaces of the lens deviates from the optical axis. Further, conditions of a following formula are satisfied: 1.6<f1/f3<2.5 ?0.

Abstract: An eyepiece lens includes first lens group G1 having a negative refracting power including a negative meniscus lens with a concave surface facing eyepoint E.P side, second lens group G2 having a positive refracting power including a lens with both convex surfaces on both ends, and third lens group G3 having a negative refracting power including a negative lens. The first—third lens groups are arranged in an order from eyepoint E.P side, and the eyepiece lens is capable of varying a diopter by moving the second lens group along an optical axis. The eyepiece lens is configured by aspherical surfaces to make the positive refracting power weak while at least one surface of the convex surfaces of the lens deviates from the optical axis. Further, conditions of a following formula are satisfied: 1.6<f1/f3<2.5 ?0.