Abstract: An optical system used in an imaging apparatus includes an optical element. In a case where the optical element is disposed on a magnification side with respect to an intersection point of an optical axis and a chief paraxial ray, the optical element is a negative lens, and in a case where the optical element is disposed on a reduction side with respect to the intersection point, the optical element is a positive lens. The optical element is configured to satisfy all of the following conditional expressions: 30??d?40 1.225?[nd?(14.387/?d)]?1.276 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d represents an Abbe number of the optical element, ?gF is a partial dispersion ratio of the optical element for g-line and F-line, and nd is a refractive index of the optical element for d-line.

Abstract: An optical system includes a negative lens satisfying the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the negative lens, ?gF is a partial dispersion ratio of the negative lens at a g-line and an F-line, and nd is a refractive index of the negative lens at a d-line.

Abstract: A conversion lens having a negative refractive power includes a positive lens GP. The positive lens GP satisfies all the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the positive lens GP, ?gF is a partial dispersion ratio of the positive lens GP for g-line and F-line, and nd is a refractive index of the positive lens GP for d-line.

Abstract: An optical system includes an optical element. When the optical element is disposed on a magnification side with respect to an intersection point between an optical axis and a chief paraxial ray, the optical element is a positive lens. When the optical element is disposed on a reduction side with respect to the intersection point, the optical element is a negative lens. The optical element satisfies all of the following conditional expressions: 30??d?40 1.225?[nd?(14.387/?d)]?1.276 0.4300?[?gF?(2.9795/?d)]?0.5010 where ?d is Abbe number of the optical element, ?gF is a partial dispersion ratio of the optical element for g-line and F-line, and nd is a refractive index of the optical element for d-line.

Abstract: Provided is a zoom lens, including: a front lens group only including one or more positive lens unit; a magnification-varying lens unit consisting of a negative lens unit which moves during zooming; and a positive rear lens group including a plurality of lens units, in which an interval between adjacent lens units is changed during zooming, in which front lens group includes a positive focusing unit La, in which rear lens group includes a focusing unit Lb, in which focusing unit La moves toward object side and focusing unit Lb moves toward one of object side and image side, during focusing from infinity to close distance, and a movement amount of focusing unit La at a wide angle end during focusing from infinity to closest distance, and a movement amount of focusing unit La at a telephoto end during focusing from infinity to closest distance are each appropriately set.

Abstract: Provided is an optical system, including, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a positive refractive power; a third lens unit having a negative refractive power; and a fourth lens unit having a positive refractive power, in which the second lens unit is configured to move in an optical axis direction during focusing, in which the third lens unit is configured to move, during image blur correction, in a direction having a vertical direction component with respect to an optical axis, and in which a configuration of the first lens unit and arrangement of an aperture stop and the third lens unit are each appropriately set.

Abstract: A zoom lens includes a front unit including one lens unit having a negative refractive power, and a rear unit including an aperture stop and one or more lens units and having a positive refractive power as a whole, and an interval between adjacent lens units changes during zooming such that an interval between the front unit and rear unit decreases at a telephoto end when compared to a wide angle end. The front unit includes a negative lens G11 in a position closest to the object side, and a lens surface of the negative lens G11 on the image side has an aspherical shape by which the positive refractive power increases from a center to an edge. Various parameters for the zoom lens according to the present invention are properly set.

Abstract: A zoom lens includes, from the object side to the image side, first to sixth lens units having positive, negative, positive, negative, positive, negative refracting powers. In zooming from the wide angle end to the telephoto end, the lens units are moved such that the distance between the first and second lens units increases, the distance between the second and third lens units decreases, the distance between the third and fourth lens units increases, and the distance between the fourth and fifth lens units decreases. In focusing from an infinitely distant object to a near object, the sixth lens unit is moved toward the image side. The distance between the rear principal point of the second lens unit and the front principal point of the rear lens group at the wide angle end, and the focal length of the rear lens group at the wide angle end are appropriately set.

Abstract: A zoom lens includes a front unit including one lens unit having a negative refractive power, and a rear unit including an aperture stop and one or more lens units and having a positive refractive power as a whole, and an interval between adjacent lens units changes during zooming such that an interval between the front unit and rear unit decreases at a telephoto end when compared to a wide angle end. The front unit includes a negative lens G11 in a position closest to the object side, and a lens surface of the negative lens G11 on the image side has an aspherical shape by which the positive refractive power increases from a center to an edge. Various parameters for the zoom lens according to the present invention are properly set.

Abstract: An optical system includes a first lens unit, an aperture stop, and a second lens unit having a positive refractive power. The first lens unit includes a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens unit includes a cemented lens, a fifth lens having a negative refractive power and a concave surface facing an object side, and a sixth lens having a positive refractive power and a convex surface facing an image side. In the cemented lens, a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented. A distance D1 from an object-side lens surface vertex of the first lens to the aperture stop and a distance Dt from the object-side lens surface vertex of the first lens to an image plane are appropriately set.

Abstract: The zoom lens includes first to fourth lens units respectively having negative, positive, negative and positive refractive powers and being moved during zooming. The first lens unit includes 1-1 and 1-2 negative lenses each having a meniscus shape with an object side convex surface. The conditions of ?4.0<f11/fw<?1.5,1.5<(R11b+R11a)/(R11b?R11a)<5.0 and 1.4<h12/D12<2.0 are satisfied where f11 represents a focal length of the 1-1 lens, fw represents a focal length of the zoom lens at a wide-angle end, R11a and R11b respectively represent curvature radii of the object side surface and an image side concave surface of the 1-1 lens, h12 represents half of an effective diameter of an image side aspheric surface of the 1-2 lens, and D12 represents a distance from an effective diameter position in the image side surface of the 1-2 lens to an apex of the image side aspheric surface thereof.

Abstract: An optical system includes a first lens unit, an aperture stop, and a second lens unit having a positive refractive power. The first lens unit includes a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens unit includes a cemented lens, a fifth lens having a negative refractive power and a concave surface facing an object side, and a sixth lens having a positive refractive power and a convex surface facing an image side. In the cemented lens, a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented. A distance D1 from an object-side lens surface vertex of the first lens to the aperture stop and a distance Dt from the object-side lens surface vertex of the first lens to an image plane are appropriately set.

Abstract: A zoom lens includes, from the object side to the image side, first to sixth lens units having positive, negative, positive, negative, positive, negative refracting powers. In zooming from the wide angle end to the telephoto end, the lens units are moved such that the distance between the first and second lens units increases, the distance between the second and third lens units decreases, the distance between the third and fourth lens units increases, and the distance between the fourth and fifth lens units decreases. In focusing from an infinitely distant object to a near object, the sixth lens unit is moved toward the image side. The distance between the rear principal point of the second lens unit and the front principal point of the rear lens group at the wide angle end, and the focal length of the rear lens group at the wide angle end are appropriately set.