Abstract: A lens unit includes a variable magnification optical system provided with a stop that adjusts a light amount and a processor that controls an opening amount of the stop based on information on a magnification change of the variable magnification optical system. In a case where a maximum value and a minimum value of an F-Number in the entire variable magnification region of the variable magnification optical system are respectively Fmax and Fmin and an average value of an F-Number at a wide angle end and an F-Number at a telephoto end of the variable magnification optical system is Fave, the processor is configured to control the opening amount within a range satisfying 3 < {(Fmax - Fmin)/Fave} × 100 < 10.

Abstract: An imaging lens consists of a front group, an aperture stop, and a rear group, in order from an object side. The rear group includes at least one Lp lens that is made of a resin, has a positive refractive power, and is cemented to a lens. Assuming that an Abbe number and a refractive index of the Lp lens are respectively ?p and Np, the Lp lens satisfies Conditional Expression represented by 120<?p+94.24×Np<180. The imaging lens satisfies predetermined conditional expressions.

Abstract: A zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group in order from an object side. In a case of magnification, the first lens group, the second lens group, and the third lens group move. The third lens group consists of a third a lens group that does not move in a case of image shake correction, a third b lens group that moves in the case of the image shake correction, and a third c lens group that does not move in the case of the image shake correction in order from the object side. The third b lens group consists of a positive lens and a negative lens. A predetermined conditional expression related to the third b lens group is satisfied.

Abstract: The imaging lens consists of, in order from the object side, a first lens group having a positive refractive power, a stop, a second lens group having a positive refractive power, and a third lens group. The third lens group includes one or more positive lenses and one or more negative lenses. During focusing, an entirety of the first lens group, the stop, and the second lens group, or an entirety of the second lens group integrally moves as a focus group, and the third lens group remains stationary with respect to an image plane. The imaging lens satisfies predetermined conditional expressions.

Abstract: An imaging lens consists of, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group. During focusing, only the second lens group moves. The imaging lens satisfies a conditional expression: ?0.5<f/f3<0.38 regarding the focal length f of the imaging lens and the focal length f3 of the third lens group in a state where an object at infinity is in focus.

Abstract: The imaging lens consists of, in order from an object side, a positive first lens group, a positive second lens group, and a negative third lens group. During focusing, only the second lens group moves. The first lens group includes a stop. The second lens group includes one or more cemented lenses in which a negative lens and a positive lens are cemented. The number of the positive lenses included in the second lens group is equal to or greater than three.

Abstract: A zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group in order from an object side. In a case of magnification, the first lens group, the second lens group, and the third lens group move. The third lens group consists of a third a lens group that does not move in a case of image shake correction, a third b lens group that moves in the case of the image shake correction, and a third c lens group that does not move in the case of the image shake correction in order from the object side. The third b lens group consists of a positive lens and a negative lens. A predetermined conditional expression related to the third b lens group is satisfied.

Abstract: The imaging lens consists of, in order from an object side, a positive first lens group, a positive second lens group, and a negative third lens group. During focusing, only the second lens group moves. The first lens group includes a stop. The second lens group includes one or more cemented lenses in which a negative lens and a positive lens are cemented. The number of the positive lenses included in the second lens group is equal to or greater than three.

Abstract: The imaging lens consists of a positive first lens group remaining stationary during focusing, a negative second lens group, a positive third lens group, and a negative fourth lens group remaining stationary during focusing, in order from an object side. During focusing from the infinite object to the closest object, the second lens group moves to an image side, the third lens group moves to the object side, and the fourth lens group consists of a fourth-a lens group which is a vibration-proof lens group and a fourth-b lens group, in order from the object side. In the imaging lens, predetermined conditional expressions are satisfied.

Abstract: The imaging lens consists of a positive first lens group remaining stationary during focusing, a negative second lens group, a positive third lens group, and a negative fourth lens group remaining stationary during focusing, in order from an object side. During focusing from the infinite object to the closest object, the second lens group moves to an image side, the third lens group moves to the object side, and the fourth lens group consists of a fourth-a lens group which is a vibration-proof lens group and a fourth-b lens group, in order from the object side. In the imaging lens, predetermined conditional expressions are satisfied.

Abstract: A zoom lens is constituted by, in order from the object side: 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. The distance between the first and second lens groups constantly increases, the distance between the second and third lens groups constantly decreases, the distance between the third and fourth lens groups constantly changes, and the distance between the fourth and fifth lens groups constantly increases when changing magnification from the wide angle end to the telephoto end. The first lens group is constituted by three lenses, which are negative, positive, and positive in order from the object side. The second lens group is constituted by five lenses, which are negative, negative, positive, positive, and negative in order from the object side. The fifth lens group is constituted by a single lens component.

Abstract: A macro lens system includes, in this order from an object side: a positive first lens group; a negative second lens group; a positive third lens group; a positive fourth lens group; a positive fifth lens group; and a negative sixth lens group. The first lens group is constituted by three lenses. The second lens group, the fourth lens group, and the fifth lens group are independently moved in the direction of the optical axes thereof when focusing from an object at infinity to an object at a most proximate distance.

Abstract: A macro lens system includes, in this order from an object side: a positive first lens group; a negative second lens group; a positive third lens group; a negative fourth lens group; a positive fifth lens group; and a negative sixth lens group. The first lens group is constituted by three lenses. The second lens group, the fourth lens group, and the fifth lens group are independently moved in the direction of the optical axes thereof when focusing from an object at infinity to an object at a most proximate distance. The second lens group moves toward the image side and the fourth lens group moves toward the object side when focusing from an object at infinity to an object at a most proximate distance.

Abstract: A zoom lens consists of, in order from the object-side, a first lens-group having positive refractive power, and which is fixed during magnification change, a second lens-group having negative refractive power, and which moves during magnification change, a third lens-group having positive refractive power, and which is fixed during magnification change, a fourth lens-group having positive refractive power, and which moves during magnification change, and a fifth lens-group having negative refractive power, and which moves during magnification change. The first lens-group consists of, in order from the object-side, a front group having negative refractive power, a reflection member that bends an optical path and a rear group having positive refractive power. The fourth lens-group includes at least a cemented lens of a positive lens and a negative lens, and the following conditional expression (1) is satisfied: 0.8<IH/fw??(1).

Abstract: A zoom lens is constituted by, in order from the object side: 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. The distance between the first and second lens groups constantly increases, the distance between the second and third lens groups constantly decreases, the distance between the third and fourth lens groups constantly changes, and the distance between the fourth and fifth lens groups constantly increases when changing magnification from the wide angle end to the telephoto end. The first lens group is constituted by three lenses, which are negative, positive, and positive in order from the object side. The second lens group is constituted by five lenses, which are negative, negative, positive, positive, and negative in order from the object side. The fifth lens group is constituted by a single lens component.

Abstract: A zoom lens consists of, in order from the object-side, a first lens-group having positive refractive power, and which is fixed during magnification change, a second lens-group having negative refractive power, and which moves during magnification change, a third lens-group having positive refractive power, and which is fixed during magnification change, a fourth lens-group having positive refractive power, and which moves during magnification change, and a fifth lens-group having negative refractive power, and which moves during magnification change. The first lens-group consists of, in order from the object-side, a front group having negative refractive power, a reflection member that bends an optical path and a rear group having positive refractive power. The fourth lens-group includes at least a cemented lens of a positive lens and a negative lens, and the following conditional expression (1) is satisfied: 0.8<IH/fw??(1).

Abstract: A macro lens system includes, in this order from an object side: a positive first lens group; a negative second lens group; a positive third lens group; a negative fourth lens group; a positive fifth lens group; and a negative sixth lens group. The first lens group is constituted by three lenses. The second lens group, the fourth lens group, and the fifth lens group are independently moved in the direction of the optical axes thereof when focusing from an object at infinity to an object at a most proximate distance. The second lens group moves toward the image side and the fourth lens group moves toward the object side when focusing from an object at infinity to an object at a most proximate distance.

Abstract: A macro lens system includes, in this order from an object side: a positive first lens group; a negative second lens group; a positive third lens group; a positive fourth lens group; a positive fifth lens group; and a negative sixth lens group. The first lens group is constituted by three lenses. The second lens group, the fourth lens group, and the fifth lens group are independently moved in the direction of the optical axes thereof when focusing from an object at infinity to an object at a most proximate distance.

Abstract: An imaging device with a short length and small aberration is provided. A total length D of an image-forming optical system is less than 3.6 mm. A maximum incidence angle of a principle ray on an image forming plane exceeds 33°. Conditions f/fL<?1.50 or f/fL<?0.9, and D/f<1.10 are satisfied where f denotes a focal length of the entire image-forming optical system and fL denotes a focal length of a last lens.

Abstract: A zoom lens includes a positive first lens group, which is fixed during changing magnification and during focusing, a negative second lens group, which is moved during changing magnification, a positive third lens group, which is fixed during changing magnification and during focusing, a positive fourth lens group, which is moved during changing magnification and during focusing, and a negative fifth lens group, which is moved during changing magnification, which are in this order from an object side. A lens group constituting the first lens group consists of a negative front group and a positive rear group in this order from the object side. The second lens group consists of four lenses of a negative lens, a positive lens, a negative lens, and a positive lens or a negative lens arranged in this order from the object side.