Abstract: A variable magnification optical system includes a plurality of lens element, and 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 at least one lens unit. An aperture stop is either positioned between the second lens unit and the third lens unit, or positioned in the third lens unit. At the time of zooming from a wide angle end to a telephoto end, the first lens unit is fixed, the second lens unit moves from the object side to an image-plane side, and at least one of lens units positioned on an image side of the aperture stop moves. The first lens unit includes at least four positive lens elements and at least two negative lens elements.

Abstract: A variable magnification optical system includes 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 at least one lens unit. A second predetermined positive lens element satisfies conditional expressions (1) and (2) and a second predetermined negative lens element satisfies the following conditional expressions (3) and (4). The second lens unit includes three sub-lens units and the following conditional expressions (5) and (6) are satisfied: 0.520<(?g,F)G2p<0.610??(1), 0.680<(?C,t)G2p<0.900??(2), 0.520<(?g,F)G2n<0.560??(3), 0.750<(?C,t)G2n<0.900??(4), ?0.25<fG21/fG22<0.90??(5), and ?0.70<fG21/fG23<0.40??(6).

Abstract: A variable magnification optical system includes 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 at least one lens unit. A second predetermined positive lens element satisfies conditional expressions (1) and (2) and a second predetermined negative lens element satisfies the following conditional expressions (3) and (4). The second lens unit includes three sub-lens units and the following conditional expressions (5) and (6) are satisfied: 0.520<(?g,F)G2p<0.610??(1), 0.680<(?C,t)G2p<0.900??(2), 0.520<(?g,F)G2n<0.560??(3), 0.750<(?C,t)G2n<0.900??(4), ?0.25<fG21/fG22<0.90??(5), and ?0.70<fG21/fG23<0.40??(6).

Abstract: A variable magnification optical system includes a plurality of lens element, and 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 at least one lens unit. An aperture stop is either positioned between the second lens unit and the third lens unit, or positioned in the third lens unit. At the time of zooming from a wide angle end to a telephoto end, the first lens unit is fixed, the second lens unit moves from the object side to an image-plane side, and at least one of lens units positioned on an image side of the aperture stop moves. The first lens unit includes at least four positive lens elements and at least two negative lens elements.

Abstract: A wide angle lens includes in order from an object side, a front lens unit having a positive refractive power, one focusing lens having a negative refractive power, and a rear lens unit having a positive refractive power, and at the time of focusing, the focusing lens moves on an optical axis, and the following conditional expressions (1) and (2) are satisfied. 0.1<f1/SSD<0.5??(1) 3.

Abstract: A wide angle lens includes in order from an object side, a front lens unit having a positive refractive power, one focusing lens having a negative refractive power, and a rear lens unit having a positive refractive power, and at the time of focusing, the focusing lens moves on an optical axis, and the following conditional expressions (1) and (2) are satisfied. 0.1<f1/SSD<0.5??(1) 3.

Abstract: A zoom lens consists of, in order from the 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, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. The first lens unit and the second lens unit move during zooming from the wide angle end to the telephoto end. The zoom lens satisfies the following conditional expressions (1), (2), and (3): ft/fw>6.0??(1), Fno(T)<3.5??(2),and ?d/ft<0.6??(3).

Abstract: A zoom lens consists of, in order from the 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, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. The first lens unit and the second lens unit move during zooming from the wide angle end to the telephoto end. The zoom lens satisfies the following conditional expressions (1), (2), and (3): ft/fw>6.0??(1), Fno(T)<3.5??(2),and ?d/ft<0.6??(3).

Abstract: An image pickup apparatus includes: a zoom lens; an image pickup element having an image pickup surface which receives an image which has been formed by the zoom lens, and converts to an electric signal; a shading correction parameter storage section which stores a shading correction parameter which differs at a front-surface side and a rear-surface side with respect to a center of an image, which is for correcting asymmetric shading at the front-surface side and the rear-surface side of the zoom lens; and a shading correction section which carries out correction operation of an image which has been picked up by the image pickup element, based on the shading correction parameter of the shading correction parameter storage section. When an object having a uniform brightness is captured, at any state from the wide angle end to the telephoto end, the zoom lens satisfies conditional expression (A).

Abstract: A zoom lens comprises in order from an object side, a first lens unit, a second lens unit, a third lens unit, a fourth lens unit, and a fifth lens unit having, respectively, a positive, negative, positive, negative, and positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the first, third, and fourth lens units move toward the object side. A distance between the first and second lens units increase, a distance between the second and third lens units decrease, a distance between the third lens unit and the fourth lens unit changes, and a distance between the fourth lens unit and the fifth lens unit increases. The zoom lens satisfies the following expressions: 1.54<?4T/?4w<3.0??(1a) 1.0<?3T/?3w<5.0??(2) 1.0<?5T/?5w<3.0??(3).

Abstract: An image pickup apparatus includes a zoom lens, and an image pickup element having an image pickup surface which receives optically an image formed by the zoom lens, and which converts the image received to an electric signal. The image pickup apparatus satisfies the following conditional expressions (1) Lv 1 Er/Lv 1 EL<0.49, (2) 0.93<Lv 1 Ef/IHs, and (3) Lv 1 Ef/Lv 1 Er<0.99.

Abstract: A zoom lens comprises in order from an object side, a first lens unit, a second lens unit, a third lens unit, a fourth lens unit, and a fifth lens unit having, respectively, a positive, negative, positive, negative, and positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the first, third, and fourth lens units move toward the object side. A distance between the first and second lens units increase, a distance between the second and third lens units decrease, a distance between the third lens unit and the fourth lens unit changes, and a distance between the fourth lens unit and the fifth lens unit increases. The zoom lens satisfies the following expressions: 1.54<?4T/?4w<3.0??(1a) 1.0<?3T/?3w<5.0??(2) 1.0<?5T/?5w<3.0??(3).

Abstract: An image pickup apparatus, which comprises, in order from the object side, an aperture member having an opening section, a zoom lens changing a magnification by properly changing distances between a plurality of lens units, and an image pickup device, is provided with a flare stop which has an opening section with a set shape and is integrated with the most object side lens unit in the plurality of the lens units, the opening section of the aperture member does not intercept an effective light beam in the wide-angle position and intercepts a part of the effective light beam in the telephoto position, and the flare stop does not intercept in the wide-angle position the effective light beam having passed through the opening section of the aperture member and intercepts in the telephoto position a light ray which is included in the effective light beam passing through the opening section of the aperture member and strikes the edge of the opening section of the aperture member to be scattered.

Abstract: An apparatus includes a zoom lens and an image pickup element. The zoom lens includes an optical path reflecting lens group including a reflecting member and having a positive refracting power, a movable negative lens group that is disposed in the optical path on the image side of the optical path reflecting lens group, has a negative refracting power, and moves during zooming, a movable positive lens group that is disposed in the optical path on the image side of the movable negative lens group, has a positive refracting power, and moves during zooming, and an aperture stop disposed in the optical path between the movable negative lens group and the movable positive lens group. The optical path reflecting lens group is a lens group located closest to the object side in the zoom lens.

Abstract: A zoom lens includes, in order from the object side, an object side lens group having a negative refracting power at the wide angle end and including at least one negative lens unit, and an image side lens group having a positive refracting power at the wide angle end and including at least one positive lens unit including a cemented doublet lens component. The distance between the two lens groups is smaller at the telephoto end than at the wide angle end. The cemented doublet lens component includes, in order from the object side, a negative object side lens having a concave surface facing the image side, and positive image side lens having a meniscus shape with a concave surface facing the image side. The cemented doublet lens component is located closest to the image side in the positive lens unit. The zoom lens satisfies specific conditions.

Abstract: An image pickup apparatus includes a zoom lens, and an image pickup element having an image pickup surface which receives an image which has been formed by the zoom lens, and converts to an electric signal. When an object having a uniform brightness is captured, at any state from the wide angle end to the telephoto end, the zoom lens satisfies conditional expression (A). The image pickup apparatus includes a shading correction parameter storage section which stores a shading correction parameter which differs at a front-surface side and a rear-surface side with respect to a center of an image, which is for correcting asymmetric shading at the front-surface side and the rear-surface side of the zoom lens, and a shading correction section which carries out correction operation of an image which has been picked up by the image pickup element, based on the shading correction parameter of (stored in) the shading correction parameter storage section.

Abstract: A zoom lens system has, in order from an object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, an aperture stop, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power; during magnification change, the first lens unit, the second lens unit, the third lens unit, the fourth lens unit and the aperture stop move; the first lens unit includes a negative lens and a positive lens in order from the object side; the second lens unit includes a negative lens and a positive lens in order from the object side; the third lens unit includes three or less lenses including one positive lens and one negative lens; and the fourth lens unit includes one positive lens.

Abstract: An image pickup apparatus includes a zoom lens, and an image pickup element having an image pickup surface which receives optically an image formed by the zoom lens, and which converts the image received to an electric signal. The image pickup apparatus satisfies the following conditional expressions (1), (2), and (3). Lv 1 Er/Lv 1 EL<0.49 ??(1) 0.93<Lv 1 Ef/IHs ??(2) Lv 1 Ef/Lv 1 Er<0.

Abstract: A zoom lens includes, in order from the object side, an object side lens group having a negative refracting power at the wide angle end and including at least one negative lens unit, and an image side lens group having a positive refracting power at the wide angle end and including at least one positive lens unit including a cemented doublet lens component. The distance between the two lens groups is smaller at the telephoto end than at the wide angle end. The cemented doublet lens component includes, in order from the object side, a negative object side lens having a concave surface facing the image side, and positive image side lens having a meniscus shape with a concave surface facing the image side. The cemented doublet lens component is located closest to the image side in the positive lens unit. The zoom lens satisfies specific conditions.

Abstract: A zoom lens includes, in order from the object side thereof, a first lens unit G1 having a positive refracting power, a second lens unit G2 having a negative refracting power, and a third lens unit G3 having a positive refracting power, wherein zooming is performed by changing distances between the lens units, the second lens unit has two negative lens elements and one positive lens element, and the lens element located closest to the object side is a negative lens element. The zoom lens satisfies the following conditions: 0.60<?d2G/Imw<1.95??(1-1) and 1.830<N2ave<2.000??(1-2), where the term “lens element” refers to an optical member that satisfies 0.1<L/Imw.