Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from a short focal length extremity to a long focal length extremity, at least the first lens group, the second lens group and the fourth lens group are moved in the optical axis direction of the zoom lens. The third lens group includes a negative first sub-lens group and a negative second sub-lens group, in that order from the object side, the second sub-lens group is provided with a negative single lens element and a positive single lens element, and an air lens is formed between the negative single lens element and the positive single lens element.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from a short focal length extremity to a long focal length extremity, at least the first lens group, the second lens group and the fourth lens group are moved in the optical axis direction of the zoom lens. The third lens group includes a negative first sub-lens group and a negative second sub-lens group, in that order from the object side, the second sub-lens group is provided with a negative single lens element and a positive single lens element, and an air lens is formed between the negative single lens element and the positive single lens element.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first lens group, the second lens group and the fourth lens group are moved in the optical axis direction. The third lens group includes a negative first sub-lens group and a negative second sub-lens group, in that order from the object side. The second sub-lens group is provided with a negative single lens element and a positive single lens element, wherein an air lens is formed between the negative single lens element and the positive single lens element.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in the optical axis direction. The second lens group includes at least four lens elements. Each of the third, fourth and fifth lens groups includes a plurality of lens elements. The following conditions (1) and (2) are satisfied: 1.60<f1/f5<2.46 ??(1), and ?2.46<f4/f3<?1.80 ??(2), wherein f1, f3, f4 and f5 designate the focal lengths of the first, third, fourth and fifth lens groups, respectively.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group having a plurality of lens elements. During zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in an optical axis direction. A surface closest to the image side of the zoom lens system is a concave surface facing the image side. The following condition (1) is satisfied: 0.52<(m345t/m345w)/(ft/fw)<0.70??(1), wherein m345w and m345t designate, at the short and long focal length extremities, respectively, the combined lateral magnification of the third, fourth and fifth lens groups when focused on an object at infinity; and fw and ft designate the focal length of the zoom lens system at the short and long focal length extremities, respectively.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in the optical axis direction. The second lens group includes at least four lens elements. Each of the third, fourth and fifth lens groups includes a plurality of lens elements. The following conditions (1) and (2) are satisfied: 1.60<f1/f5<2.46 ??(1), and ?2.46<f4/f3<?1.80 ??(2), wherein f1, f3, f4 and f5 designate the focal lengths of the first, third, fourth and fifth lens groups, respectively.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group having a plurality of lens elements. During zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in an optical axis direction. A surface closest to the image side of the zoom lens system is a concave surface facing the image side. The following condition (1) is satisfied: 0.52<(m345t/m345w)/(ft/fw)<0.70??(1), wherein m345w and m345t designate, at the short and long focal length extremities, respectively, the combined lateral magnification of the third, fourth and fifth lens groups when focused on an object at infinity; and fw and ft designate the focal length of the zoom lens system at the short and long focal length extremities, respectively.

Abstract: A close-distance correcting lens system includes a positive first lens group and a negative second lens group, wherein traveling distances of the first lens group and the second lens group toward the object side differ from each other when carrying out a focusing operation on an object at infinity to an object at a close distance. The first lens group includes a positive first sub lens group, a negative second sub lens group, a diaphragm, and a positive third sub lens group, in that order from the object side. The second sub lens group includes an image-stabilizing lens group which is arranged to move in a direction orthogonal to the optical axis to change an imaging position of the object image to thereby correct any image shake of the object image.

Abstract: A large-aperture telephoto lens system includes a positive first lens group, a negative second lens group, and a positive third lens group, in that order from the object side, wherein the second lens group serves as a focusing lens group which is moved during focusing on an object at infinity to an object at a finite distance, wherein the following conditions (1) and (2) are satisfied: ?4<f/f2<?3??(1), and 1.3<f/f3<2.3??(2), wherein f designates the focal length of the entire large-aperture telephoto lens system, f2 designates the focal length of the second lens group, and f3 designates the focal length of the third lens group.

Abstract: A superwide-angle lens system includes a positive front lens group and a negative rear lens group, in that order from the object side, wherein the negative rear lens group serves as a focusing lens group that is moved in the optical axis direction when focusing on an object at infinity to an object at a finite distance. The following condition (1) is satisfied: 1.1<mR<2.0??(1), wherein mR designates the lateral magnification of the negative rear lens group when focusing on an object at infinity.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first lens group, the second lens group and the fourth lens group are moved in the optical axis direction. The third lens group includes a negative first sub-lens group and a negative second sub-lens group, in that order from the object side. The second sub-lens group is provided with a negative single lens element and a positive single lens element, wherein an air lens is formed between the negative single lens element and the positive single lens element.

Abstract: A superwide-angle lens system includes a positive front lens group and a negative rear lens group, in that order from the object side, wherein the negative rear lens group serves as a focusing lens group that is moved in the optical axis direction when focusing on an object at infinity to an object at a finite distance. The following condition (1) is satisfied: 1.1<mR<2.0??(1), wherein mR designates the lateral magnification of the negative rear lens group when focusing on an object at infinity.

Abstract: A large-aperture telephoto lens system includes a positive first lens group, a negative second lens group, and a positive third lens group, in that order from the object side, wherein the second lens group serves as a focusing lens group which is moved during focusing on an object at infinity to an object at a finite distance, wherein the following conditions (1) and (2) are satisfied: ?4<f/f2<?3??(1), and 1.3<f/f3<2.3??(2), wherein f designates the focal length of the entire large-aperture telephoto lens system, f2 designates the focal length of the second lens group, and f3 designates the focal length of the third lens group.

Abstract: A macro lens system includes a positive first lens group, a negative second lens group, a positive third lens group, and a negative fourth lens group, in that order from the object. Upon focusing from an infinite photographic distance to a life-sized photographic distance, the first lens group remains stationary with respect to the imaging plane, and the second and third lens groups move along the optical axis direction. The macro lens system satisfies the following condition: ?4.6<f2/fi<?3.0 wherein f2 designates the focal length of the second lens group; and fi the focal length of the entire the macro lens system when an object at infinity is in an in-focus state.

Abstract: A macro lens system includes a positive first lens group, a negative second lens group, a positive third lens group, and a negative fourth lens group, in that order from the object. Upon focusing from an infinite photographic distance to a life-sized photographic distance, the first lens group remains stationary with respect to the imaging plane, and the second and third lens groups move along the optical axis direction. The macro lens system satisfies the following condition: ?4.6<f2/fi<?3.0??(1) wherein f2 designates the focal length of the second lens group; and fi the focal length of the entire the macro lens system when an object at infinity is in an in-focus state.