Abstract: The imaging lens consists of, in order from the object side, a first lens group, an aperture stop, a second lens group having a positive refractive power. During focusing from a distant object to a close-range object, the first lens group remains stationary, and the aperture stop and the second lens group integrally move to the object side. The imaging lens satisfies predetermined conditional expressions relating to a focal length of the whole system, a focal length of the first lens group, a principal point position of the second lens group, a focal length of the second lens group, a back focal length, and the like.

Abstract: An image processing device, an image processing system, and an image processing method capable of easily correcting image deterioration caused by nonuniform optical characteristics around an optical axis of a lens according to a position in a rotational direction of a lens barrel are provided.

Abstract: The imaging lens includes a first lens group fixed during focusing and a positive second lens group moving to an object side during focusing from a long-distance object to a short-distance object, in order from a side closest to the object. The field curvature is adjusted by moving the first lens group or a sub-lens group within the first lens group including a lens closest to the object side, as an adjustment group. A stop fixed during the adjustment of the field curvature is disposed closer to an image side than the adjustment group. Conditional expressions relating to the focal length of the whole system, the focal length of the adjustment group, and the height of a paraxial on-axis light ray in the adjustment group are satisfied.

Abstract: The imaging lens includes a first lens group fixed during focusing and a positive second lens group moving to an object side during focusing from a long-distance object to a short-distance object, in order from a side closest to the object. The field curvature is adjusted by moving the first lens group or a sub-lens group within the first lens group including a lens closest to the object side, as an adjustment group. A stop fixed during the adjustment of the field curvature is disposed closer to an image side than the adjustment group. Conditional expressions relating to the focal length of the whole system, the focal length of the adjustment group, and the height of a paraxial on-axis light ray in the adjustment group are satisfied.

Abstract: An optical system has the entire angle of view at a wide-angle end of not smaller than 90 degrees. A spatial frequency at which an MTF of the optical system acquired using an evaluation wavelength in a region of an image formation plane in which the distance from the center of the image formation plane is not less than 80% and less than 95% of half of the length of a diagonal line of an imaging surface of an imaging element image is not more than 30% is higher at the wide-angle end than at a telephoto end. When F??(Fw×Ft) is satisfied (where F indicates the focal length of the optical system when the target image is captured, Fw indicates the focal length at the wide-angle end, and Ft indicates the focal length at the telephoto end), a sharpening processing unit performs a restoration process based on an optical transfer function of the optical system as a sharpening process.

Abstract: For causing a near-infrared light image obtained through imaging in a second imaging mode to be easily viewed while suppressing an increase in size and number of components, in a case where an imaging unit is operating in the second imaging mode, a change region where there is a change is detected through comparison with the second image data that the imaging unit has acquired before the second image data, from within the second image data acquired by the imaging unit. Combination image data obtained by combining the change region image data corresponding to the change region within the second image data with background image data of a color image generated on the basis of first image data acquired in a first imaging mode immediately before the second imaging mode by the imaging unit and corresponding to a background region different from the change region within the second image data is generated on the basis of the detection result of the change region.

Abstract: The imaging lens includes, in order from the object side, a first lens group that remains stationary during focusing; a diaphragm; and a positive second lens group that moves to the object side during focusing from a long range to a close range. The first lens group includes, in order from the object side: a negative meniscus lens that has an absolute value of a radius of curvature of an image side surface smaller than that of an object side surface, a negative lens, a positive lens, and a negative lens. The second lens group includes five or less lenses, and includes: a positive Z lens that is formed continuously in order from a most image side; a negative Y lens that has an absolute value of a radius of curvature of an object side surface smaller than that of an image side surface; and a positive X lens.

Abstract: The imaging lens includes, in order from the object side, a first lens group that remains stationary during focusing; a diaphragm; and a positive second lens group that moves to the object side during focusing from a long range to a close range. The second lens group includes a positive Z lens that is formed continuously in order from a most image side, a negative Y lens that has an absolute value of a radius of curvature of an object side surface smaller than an absolute value of a radius of curvature of an image side surface, a positive X lens, and a negative W lens that has an absolute value of a radius of curvature of an image side surface smaller than that of an object side surface. The imaging lens satisfies a conditional expression about of the radii of curvature of the X lens and the W lens.

Abstract: An imaging lens is constituted essentially by, in order from the object side to the image side, a negative first lens group, a positive second lens group, a stop, and a positive third lens group. The first lens group is constituted essentially by four or fewer lenses, has a positive lens and a negative meniscus lens provided adjacent to each other in this order from the most object side, and further has a negative lens at the most image side. The second lens group is constituted essentially by one single lens. The third lens group is constituted essentially by five or fewer lenses, and has four lenses having refractive powers of different signs adjacent to each other provided in order as lenses most toward the image side. Predetermined conditional formulae are satisfied.

Abstract: An imaging lens consists of, in order from the object side, a front group, a stop, and a rear group, wherein the front group includes, in order from the most-object side, a positive first lens, a negative second lens, a negative third lens which are adjacently disposed, and further includes a final lens of the front group adjacent to the stop, with the surface toward the stop being convex toward the image side, the rear group includes, in order from the image side, two sets of cemented lenses having positive refractive powers, which are adjacently disposed, the object-side cemented lens of the two sets of cemented lenses is formed by cementing a positive lens and a negative meniscus lens together, and the image-side cemented lens is formed by cementing a negative meniscus lens and a positive lens together.

Abstract: An imaging lens is constituted essentially by, in order from the object side to the image side, a negative first lens group, a positive second lens group, a stop, and a positive third lens group. The first lens group is constituted essentially by four or fewer lenses, has a positive lens and a negative meniscus lens provided adjacent to each other in this order from the most object side, and further has a negative lens at the most image side. The second lens group is constituted essentially by one single lens. The third lens group is constituted essentially by five or fewer lenses, and has four lenses having refractive powers of different signs adjacent to each other provided in order as lenses most toward the image side. Predetermined conditional formulae are satisfied.

Abstract: An imaging lens consists of, in order from the object side, a front group, a stop, and a rear group, wherein the front group includes, in order from the most-object side, a positive first lens, a negative second lens, a negative third lens which are adjacently disposed, and further includes a final lens of the front group adjacent to the stop, with the surface toward the stop being convex toward the image side, the rear group includes, in order from the image side, two sets of cemented lenses having positive refractive powers, which are adjacently disposed, the object-side cemented lens of the two sets of cemented lenses is formed by cementing a positive lens and a negative meniscus lens together, and the image-side cemented lens is formed by cementing a negative meniscus lens and a positive lens together.

Abstract: A variable magnification optical system consists of first lens group having negative refractive power and second lens group having positive refractive power, which are in this order from an object side, and a distance in an optical axis direction between the first lens group and the second lens group changes when magnification is changed. The second lens group consists of a positive sixth lens, a negative seventh lens, a positive eighth lens, and a cemented lens composed of a negative ninth lens and a positive tenth lens cemented together, which are in this order from the object side, and all of the three positive lenses, which are the sixth lens, the eighth lens and the tenth lens, are double-convex lenses. A predetermined formula is satisfied.

Abstract: A variable magnification optical system consists of first lens group having negative refractive power and second lens group having positive refractive power, which are in this order from an object side, and a distance in an optical axis direction between the first lens group and the second lens group changes when magnification is changed. The second lens group consists of a positive sixth lens, a negative seventh lens, a positive eighth lens, and a cemented lens composed of a negative ninth lens and a positive tenth lens cemented together, which are in this order from the object side, and all of the three positive lenses, which are the sixth lens, the eighth lens and the tenth lens, are double-convex lenses. A predetermined formula is satisfied.