Abstract: A zoom lens includes a front unit having a negative refractive power; and a rear unit having a positive refractive power, which includes an aperture stop. The front unit includes a first negative refractive power lens, a second negative refractive power lens, and a third positive refractive power lens. The first lens is nearest to an object, and has a meniscus shape with a convex surface directed toward the object side, and the second lens is on an image side of the first lens, and has a meniscus shape with a convex surface directed toward the object side. The rear unit includes a first lens unit A and a second lens unit B, wherein when zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit narrows, and a distance between the first lens unit A and the second lens unit B changes. The first lens unit A includes a first sub-lens unit having a positive refractive power, the aperture stop, and a second sub-lens unit.

Abstract: An inner focus lens system includes, in order from an object side to an image side, a first lens unit, an aperture stop, 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. The first lens unit has negative lens(es) and positive lens(es), the second lens unit has negative lens(es) and positive lens(es), the third lens unit has negative lens(es), the fourth lens unit has positive lens(es), at the time of focusing on an object at a short distance from an object at infinity, the third lens unit moves to an image side to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit, and the following conditional expression is satisfied: ?6<f3/f<?1.

Abstract: A zoom lens includes in order from an object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power, and at the time of zooming, the first lens unit is fixed, and at least two lens units positioned on an image side of the first lens unit move, and the first lens unit includes a plurality of lenses, and also has a cemented lens, and the cemented lens are included in the plurality of lenses, and the plurality of lenses includes one negative lens and three positive lenses, and the following conditional expressions (1), (2), and (3) are satisfied. 1.5<ndp<1.

Abstract: A single focal length lens includes an aperture stop and first through fourth lens units having, respectively, negative refractive power, positive refractive power, negative refractive power, and positive refractive power. Positions of the first, second, and fourth lens units are fixed. When focusing from an object at infinity to an object at a short distance, the third lens unit moves toward the image side. Conditional expressions (1), (2), and (3) are satisfied: ?5<f1/f<?0.5??(1), ?10<f3/f<?1??(2), and 0.5<f12/f<1??(3), where f1 denotes a focal length of the first lens unit, f denotes a focal length of an overall single focal length lens system when focusing to an object at infinity, f3 denotes a focal length of the third lens unit, and f12 denotes a combined focal length of the first and second lens units.

Abstract: A zoom lens includes a front unit having a negative refractive power; and a rear unit having a positive refractive power, which includes an aperture stop. The front unit includes a first negative refractive power lens, a second negative refractive power lens, and a third positive refractive power lens. The first lens is nearest to an object, and has a meniscus shape with a convex surface directed toward the object side, and the second lens is on an image side of the first lens, and has a meniscus shape with a convex surface directed toward the object side. The rear unit includes a first lens unit A and a second lens unit B, wherein when zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit narrows, and a distance between the first lens unit A and the second lens unit B changes. The first lens unit A includes a first sub-lens unit having a positive refractive power, the aperture stop, and a second sub-lens unit.

Abstract: A zoom lens includes a front unit having a negative refractive power and a rear unit having a positive refractive power, which includes an aperture stop, and the front unit includes a first lens having a negative refractive power, and the first lens has a meniscus shape of which a convex surface is directed toward the object side, and the rear unit includes a first lens unit A and a second lens unit B, and at the time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit changes.

Abstract: An inner focus lens system comprises, in order from an object side to an image side, a first lens unit, an aperture stop, 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, wherein the first lens unit has at least one negative lens and at least one positive lens, the second lens unit has at least one negative lens and at least one positive lens, the third lens unit has at least one negative lens, the fourth lens unit has at least one positive lens, at the time of focusing on an object at a short distance from an object at infinity, the third lens unit moves to an image side so as to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit, and the following conditional expression (1) is satisfied: ?6<f3/f<?1 ??(1).

Abstract: A single focal length lens includes a first lens unit having a negative refractive power, an aperture stop, 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, wherein a position of the first lens unit, a position of the second lens unit, and a position of the fourth lens unit are fixed all the time, and at the time of focusing from an object at infinity to an object at a short distance, the third lens unit moves toward the image side, and the following conditional expressions (1), (2), and (3) are satisfied: ?5<f1/f<?0.5 ??(1), ?10<f3/f<?1 ??(2), and 0.5<f12/f<1 ??(3).

Abstract: An inner focus lens system comprises, in order from an object side to an image side, a first lens unit, an aperture stop, 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, wherein the first lens unit has at least one negative lens and at least one positive lens, the second lens unit has at least one negative lens and at least one positive lens, the third lens unit has at least one negative lens, the fourth lens unit has at least one positive lens, at the time of focusing on an object at a short distance from an object at infinity, the third lens unit moves to an image side so as to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit, and the following conditional expression (1) is satisfied: ?6<f3/f<?1??(1).

Abstract: This disclosure is directed to an inner focus macrolens. The inner focus macrolens can include sequentially from an object side, a first lens unit, an aperture stop, 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, wherein the first lens unit comprises a negative lens as the closest powered lens to the object side and a positive lens, the second lens unit comprises an object side negative lens as the closest powered lens to the object side and a positive lens, the third lens unit comprises a negative lens, and the fourth lens unit comprises a positive lens.

Abstract: Systems and apparatuses provide for an imaging optical system that facilitates aberration reductions while ensuring brightness and a proper angle of view. Embodiments provide for (i) an imaging optical system that allows for a simple structure of a focusing mechanism and (ii) an imaging apparatus incorporating such an imaging optical system. The imaging optical system may include, from the object side to the image side, a first lens group having positive refracting power, an aperture stop, and a second lens group having positive power, in which the first lens group consists of three lens subgroups, having positive, negative and positive refracting powers, respectively, from the object side to the image side.

Abstract: A zoom lens includes in order from an object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power, and at the time of zooming, the first lens unit is fixed, and at least two lens units positioned on an image side of the first lens unit move, and the first lens unit includes a plurality of lenses, and also has a cemented lens, and the cemented lens are included in the plurality of lenses, and the plurality of lenses includes one negative lens and three positive lenses, and the following conditional expressions (1), (2), and (3) are satisfied. 1.5<ndp<1.

Abstract: A zoom lens includes a front unit having a negative refractive power and a rear unit having a positive refractive power, which includes an aperture stop, and the front unit includes a first lens having a negative refractive power, and the first lens has a meniscus shape of which a convex surface is directed toward the object side, and the rear unit includes a first lens unit A and a second lens unit B, and at the time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit changes.

Abstract: A zoom lens comprising, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. Each distance between the first lens unit and the second lens unit, between the third lens unit and the fourth lens unit, and between the fourth lens unit and the fourth lens unit at the telephoto end is longer than at the wide angle end, and a distance between the second lens unit and the third lens unit at the telephoto end is shorter than at the wide angle end, and the following conditional expressions are satisfied. 2<mg3t/mg3w<6 1.2<mg5t/mg5w<4 0.02<f5/ft<0.

Abstract: This disclosure is directed to an inner focus macrolens. The inner focus macrolens can include sequentially from an object side, a first lens unit, an aperture stop, 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, wherein the first lens unit comprises a negative lens as the closest powered lens to the object side and a positive lens, the second lens unit comprises an object side negative lens as the closest powered lens to the object side and a positive lens, the third lens unit comprises a negative lens, and the fourth lens unit comprises a positive lens.

Abstract: A zoom lens comprising, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. Each distance between the first lens unit and the second lens unit, between the third lens unit and the fourth lens unit, and between the fourth lens unit and the fourth lens unit at the telephoto end is longer than at the wide angle end, and a distance between the second lens unit and the third lens unit at the telephoto end is shorter than at the wide angle end, and the following conditional expressions are satisfied. 2<mg3t/mg3w<6 1.2<mg5t/mg5w<4 0.02<f5/ft<0.

Abstract: A zoom lens comprising, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. Each distance between the first lens unit and the second lens unit, between the third lens unit and the fourth lens unit, and between the fourth lens unit and the fourth lens unit at the telephoto end is longer than at the wide angle end, and a distance between the second lens unit and the third lens unit at the telephoto end is shorter than at the wide angle end, and the following conditional expressions are satisfied. 2<mg3t/mg3w<6 1.2<mg5t/mg5w<4 0.02<f5/ft<0.

Abstract: An imaging optical system including, from the object side to the image side, a first lens group having positive refracting power, an aperture stop, and a second lens group having positive power, in which the first lens group consists of three lens subgroups, having positive, negative and positive refracting powers, respectively, from the object side to the image side, with satisfaction of the following: 4<(LTL+fB)/fB<15??(1) 0.3<D12/IH<4??(2) where fB is an on-axis distance, from an image side-surface in the second lens group to an image plane upon focusing at infinity, LTL is an on-axis distance from an object side-surface in the first lens group to the image side-surface in the second lens group, D12 is an on-axis length from an image side-surface in the first lens group to an object side-surface in the second lens group upon focusing at infinity, and IH is a maximum image height.

Abstract: A zoom lens includes, in order from the object side to the image side along its optical path, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and including a prism reflecting member, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power, wherein the distances between the lens units vary during zooming from the wide angle end to the telephoto end, the first lens unit and the third lens unit are located closer to the ray incidence side at the telephoto end than at the wide angle end, the position of the second lens unit is fixed during zooming from the wide angle end to the telephoto end.

Abstract: An inner focus lens system comprises, in order from an object side to an image side, a first lens unit, an aperture stop, 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, wherein the first lens unit has at least one negative lens and at least one positive lens, the second lens unit has at least one negative lens and at least one positive lens, the third lens unit has at least one negative lens, the fourth lens unit has at least one positive lens, at the time of focusing on an object at a short distance from an object at infinity, the third lens unit moves to an image side so as to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit, and the following conditional expression (1) is satisfied: ?6<f3/f<?1??(1).