Abstract: A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

Abstract: The imaging lens includes only eight lenses consisting of, in order from an object side, a negative first lens, a negative second lens, a positive third lens convex toward an image side, a positive fourth lens convex toward an object side, a negative fifth lens, a positive sixth lens convex toward the image side, a positive seventh lens convex toward the object side, and a negative eighth lens, as lenses having refractive powers, in which predetermined conditional expressions are satisfied.

Abstract: Provided is a lens device provided in an imaging apparatus body including an image sensor, the lens device including a lens that includes a shake correction lens correcting a shake of an image obtained by imaging light on the image sensor, and images the light, which is incident, on the image sensor, a first drive mechanism that moves the shake correction lens in a direction in which the shake of the image is corrected, by applying power to the shake correction lens along a coordinate plane intersecting an optical axis of the lens, and a second drive mechanism that moves the shake correction lens in a direction in which the image is shifted, by applying power to the shake correction lens along the coordinate plane.

Abstract: Provided is a lens device provided in an imaging apparatus body including an image sensor, the lens device including a processor, a a memory coupled to or integrated with the processor, a lens that includes a movement lens and that images incident light on the image sensor, and a drive mechanism that moves the movement lens by applying power to the movement lens along a coordinate plane intersecting an optical axis of the lens. The processor is configured to perform, with respect to the drive mechanism, control of changing a movement amount of the movement lens based on a wavelength range of the light transmitted through the movement lens.

Abstract: A processor of a lens device is configured to acquire inclination information related to at least one of an inclination of a first drive axis of a drive mechanism with respect to a first axis of an image sensor or an inclination of a second drive axis of the drive mechanism with respect to a second axis of the image sensor, and perform, with respect to the drive mechanism, control of moving a movement lens along at least one of the first axis or the second axis based on the inclination information.

Abstract: A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

Abstract: A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

Abstract: The imaging lens consists of, in order from an object side, a first lens group, a stop, and a positive second lens group. The second lens group has a negative lens on a side closest to an object and has a single lens or a cemented lens having a positive refractive power on a side closest to an image. Predetermined conditional expressions relating to a back focus, an incidence angle of a principal light ray on the image plane, a maximum image height, a distance from a lens surface on the side closest to the object to a lens surface on the side closest to the image, a distance from an object side principal point of the second lens group to a stop, and a focal length of the second lens group are satisfied.

Abstract: The imaging lens consists of, in order from an object side, a positive first lens group and a positive second lens group. During focusing, the first lens group does not move and the second lens group moves. First and second lenses from an object side in the first lens group are a negative lens. The second lens group consists of a stop disposed on the most object side, two negative lenses, and three or four positive lenses. A lens on the most object side of the second lens group is a negative lens. A lens on the most image side of the second lens group is a positive lens. Predetermined conditional expressions are satisfied.

Abstract: A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

Abstract: The imaging lens includes only eight lenses consisting of, in order from an object side, a negative first lens, a negative second lens, a positive third lens convex toward an image side, a positive fourth lens convex toward an object side, a negative fifth lens, a positive sixth lens convex toward the image side, a positive seventh lens convex toward the object side, and a negative eighth lens, as lenses having refractive powers, in which predetermined conditional expressions are satisfied.

Abstract: The imaging lens includes at least one positive lens that satisfies predetermined conditional expressions (1) to (3) indicating conditions in which dispersion is relatively low and refractive index is high while having a negative rate of change of the refractive index. In a case where a lens that satisfies a conditional expression (4) meaning a low dispersion material is included, the lens that satisfies the conditional expression (4) satisfies a predetermined conditional expression (5).

Abstract: The imaging lens consists of, in order from an object side, a positive first lens group and a positive second lens group. During focusing, the first lens group does not move and the second lens group moves. First and second lenses from an object side in the first lens group are a negative lens. The second lens group consists of a stop disposed on the most object side, two negative lenses, and three or four positive lenses. A lens on the most object side of the second lens group is a negative lens. A lens on the most image side of the second lens group is a positive lens. Predetermined conditional expressions are satisfied.

Abstract: The imaging lens consists of, in order from an object side, a first lens group, a stop, and a positive second lens group. The second lens group has a negative lens on a side closest to an object and has a single lens or a cemented lens having a positive refractive power on a side closest to an image. Predetermined conditional expressions relating to a back focus, an incidence angle of a principal light ray on the image plane, a maximum image height, a distance from a lens surface on the side closest to the object to a lens surface on the side closest to the image, a distance from an object side principal point of the second lens group to a stop, and a focal length of the second lens group are satisfied.

Abstract: Disclosed are an imaging lens having satisfactory performance in a region of near infrared light, and an imaging apparatus including the imaging lens. The imaging lens includes, in order from an object side, as lenses having refractive power, only four lenses including a positive first lens L1, a negative second lens L2, a positive third lens L3, and a positive fourth lens L4. A conditional expression relating to a focal length fs1 of the first lens L1 with respect to s-line and a focal length fs of the entire system with respect to s-line: 0.5<fs1/fs<2.5 is satisfied.

Abstract: The imaging lens consists of, in order from an object side, a positive first lens L1, a negative second lens L2, a positive third lens L3, and a positive fourth lens L4. Conditional expressions relating to a focal length f of an entire system, a combined focal length f234 of the second lens L2 to the fourth lens L4, an Abbe number ?d1 of the first lens L1, an Abbe number ?d2 of the second lens L2, a radius of curvature R1 of a surface of the first lens L1 on the object side, and a radius of curvature R2 of a surface of the first lens L1 on an image side: 0.4<f/f234<2; ?d1<50; 5<?d1??d2<26; ?5<(R1+R2)/(R1?R2)<?0.9 are satisfied.

Abstract: The imaging lens includes at least one positive lens that satisfies predetermined conditional expressions (1) to (3) indicating conditions in which dispersion is relatively low and refractive index is high while having a negative rate of change of the refractive index. In a case where a lens that satisfies a conditional expression (4) meaning a low dispersion material is included, the lens that satisfies the conditional expression (4) satisfies a predetermined conditional expression (5).

Abstract: The imaging lens consists of, in order from an object side, a positive first lens L1, a negative second lens L2, a positive third lens L3, and a positive fourth lens L4. Conditional expressions relating to a focal length f of an entire system, a combined focal length f234 of the second lens L2 to the fourth lens L4, an Abbe number ?d1 of the first lens L1, an Abbe number ?d2 of the second lens L2, a radius of curvature R1 of a surface of the first lens L1 on the object side, and a radius of curvature R2 of a surface of the first lens L1 on an image side: 0.4<f/f234<2; ?d1<50; 5<?d1??d2<26; ?5<(R1+R2)/(R1?R2)<?0.9 are satisfied.

Abstract: Disclosed are an imaging lens having satisfactory performance in a region of near infrared light, and an imaging apparatus including the imaging lens. The imaging lens includes, in order from an object side, as lenses having refractive power, only four lenses including a positive first lens L1, a negative second lens L2, a positive third lens L3, and a positive fourth lens L4. A conditional expression relating to a focal length fs1 of the first lens L1 with respect to s-line and a focal length fs of the entire system with respect to s-line: 0.5<fs1/fs<2.5 is satisfied.

Abstract: Disclosed is an imaging lens substantially consisting of a first lens group having a positive refractive power and a second lens group having a positive refractive power, arranged in this order from the object side. Focusing is performed by moving the entire second lens group along the optical axis. The most-image-side lens of the first lens group, a lens which is second from a most-image side in the first lens group, and a lens which is third from the most-image side in the first lens group are all meniscus lenses with convex surfaces toward the image side. The imaging lens satisfies the formula: 1.0<FA/FB<8.0, where FA is the focal length of the first lens group, and FB is the focal length of the second lens group.