Abstract: A zoom lens is retractable and includes a first lens group, a second lens group and a P-lens group from an object side to an image side along an optical axis, the first lens group has a negative refractive power, and the second lens group has a reflective optical element bending an optical axis. During retraction, the second lens group moves along the optical axis to an image side, and at least a part of the first lens group is retracted into a space generated by the movement of the second lens group.

Abstract: A variable magnification optical system capable of realizing a high-resolution observation image display system that can arbitrarily change an observation field of view without changing a working distance of an observation optical system while keeping the observation optical system small in size and an imaging apparatus including the variable magnification optical system.

Abstract: To provide an image-capturing system capable of maintaining high analysis accuracy while reducing the amount of data related to image acquisition with a simple method. In order to achieve the object, the image-capturing system includes an image-capturing device configured to acquire image data of a subject, and an image-capturing control device configured to control image acquisition by the image-capturing device. The image-capturing control device includes a difference extraction means configured to extract difference data on the basis of any two image data items acquired by the image-capturing device, a change amount extraction means configured to extract change amount data on the basis of any two difference data items extracted by the difference extraction means, and a condition change means configured to change an image acquisition condition in the image-capturing device on the basis of the change amount data extracted by the change amount extraction means.

Abstract: An imaging optical system includes, in order from an object side, a first lens having negative refractive power, a second lens having positive refractive power, a third lens having positive refractive power, a fourth lens and a fifth lens, with the fourth lens and the fifth lens not cemented, in which a predetermined conditional expressions is satisfied.

Abstract: To provide an image-capturing system capable of maintaining high analysis accuracy while reducing the amount of data related to image acquisition with a simple method. In order to achieve the object, the image-capturing system includes an image-capturing device configured to acquire image data of a subject, and an image-capturing control device configured to control image acquisition by the image-capturing device. The image-capturing control device includes a difference extraction means configured to extract difference data on the basis of any two image data items acquired by the image-capturing device, a change amount extraction means configured to extract change amount data on the basis of any two difference data items extracted by the difference extraction means, and a condition change means configured to change an image acquisition condition in the image-capturing device on the basis of the change amount data extracted by the change amount extraction means.

Abstract: An observation imaging apparatus includes an insertion unit, an imaging lens, and an image sensor. The imaging lens is disposed in such a manner that an axial principal ray of an observation subject side surface of a lens is tilted with respect to a normal line passing through the center of gravity of a section of the insertion unit, the section passing through the center of an effective imaging range of the image sensor and having the smallest area. A point on the axial principal ray at which the distance between the normal line and the axial principal ray is smallest is located on the image side relative to the observation subject side surface of the lens and on the observation subject side relative to the image sensor. The observation imaging apparatus satisfies a predetermined conditional expression.

Abstract: A variable magnification optical system capable of realizing a high-resolution observation image display system that can arbitrarily change an observation field of view without changing a working distance of an observation optical system while keeping the observation optical system small in size and an imaging apparatus including the variable magnification optical system.

Abstract: An imaging lens according to the present invention includes a negative first lens, a meniscus-shaped negative second lens having a concave surface facing to an object side, a positive third lens, a positive fourth lens having a convex surface on the object side, a positive fifth lens, a negative sixth lens, and a positive seventh lens arranged in order from the object side. Furthermore, an imaging device according to the present invention includes the imaging lens.

Abstract: An observation imaging apparatus includes an insertion unit, an imaging lens, and an image sensor. The imaging lens is disposed in such a manner that an axial principal ray of an observation subject side surface of a lens is tilted with respect to a normal line passing through the center of gravity of a section of the insertion unit, the section passing through the center of an effective imaging range of the image sensor and having the smallest area. A point on the axial principal ray at which the distance between the normal line and the axial principal ray is smallest is located on the image side relative to the observation subject side surface of the lens and on the observation subject side relative to the image sensor. The observation imaging apparatus satisfies a predetermined conditional expression.

Abstract: An imaging optical system includes, in order from an object side, a first lens having negative refractive power, a second lens having positive refractive power, a third lens having positive refractive power, a fourth lens and a fifth lens, with the fourth lens and the fifth lens not cemented, in which a predetermined conditional expressions is satisfied.

Abstract: An imaging optical system according to the present invention is the imaging optical system composed by arranging a front group, a stop, and a rear group in order from an object side, a lens arranged closest to the stop in the front group is a positive lens, a lens arranged closest to the stop in the rear group is also a positive lens, and specific conditional expressions are satisfied. In addition, an imaging apparatus according to the present invention includes the imaging optical system.

Abstract: An imaging lens according to the present invention includes a negative first lens, a meniscus-shaped negative second lens having a concave surface facing to an object side, a positive third lens, a positive fourth lens having a convex surface on the object side, a positive fifth lens, a negative sixth lens, and a positive seventh lens arranged in order from the object side. Furthermore, an imaging device according to the present invention includes the imaging lens.

Abstract: An imaging optical system according to the present invention is the imaging optical system composed by arranging a front group, a stop, and a rear group in order from an object side, a lens arranged closest to the stop in the front group is a positive lens, a lens arranged closest to the stop in the rear group is also a positive lens, and specific conditional expressions are satisfied. In addition, an imaging apparatus according to the present invention includes the imaging optical system.

Abstract: The present invention provides a zoom lens that is compact in general and has an F-number to implement brightness even in the telephoto end side, and an imaging apparatus equipped with the zoom lens. The zoom lens includes, in order from an object side: a first lens group having positive refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power; and a fourth lens group having positive refractive power. At the time of zooming from the wide-angle end state to the telephoto end state, the third lens group moves so that the distance between the second lens group and the third lens group increases, and the distance between the third lens group and the fourth lens group decreases.

Abstract: A zoom lens includes a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having negative refracting power and a fifth lens group having negative refracting power in order from an object side, in which the lens groups move in magnification change from a wide angle end to a telephoto end such that a gap between the first lens group and the second lens group increases and a gap between the second lens group and the third lens group decreases, a negative lens group disposed closer to an image focusing side than a diaphragm among all lens groups is set as a focusing lens group, and the focusing lens group moves toward the image focusing side at focusing from infinity to a close object, the zoom lens satisfies a conditional expression.

Abstract: The present invention provides a zoom lens that is compact in general and has an F-number to implement brightness even in the telephoto end side, and an imaging apparatus equipped with the zoom lens. The zoom lens includes, in order from an object side: a first lens group having positive refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power; and a fourth lens group having positive refractive power. At the time of zooming from the wide-angle end state to the telephoto end state, the third lens group moves so that the distance between the second lens group and the third lens group increases, and the distance between the third lens group and the fourth lens group decreases.

Abstract: A zoom lens includes a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having negative refracting power and a fifth lens group having negative refracting power in order from an object side, in which the lens groups move in magnification change from a wide angle end to a telephoto end such that a gap between the first lens group and the second lens group increases and a gap between the second lens group and the third lens group decreases, a negative lens group disposed closer to an image focusing side than a diaphragm among all lens groups is set as a focusing lens group, and the focusing lens group moves toward the image focusing side at focusing from infinity to a close object, the zoom lens satisfies a conditional expression.

Abstract: A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; and a fourth lens group having a negative refractive power. The first lens group, the second lens group, the third lens group, and the fourth lens group are moved along an optical axis to zoom from a wide angle end to telephoto end and such that an interval between the first lens group and the second lens group decreases and distances that the second lens group and the fourth lens group are moved are equivalent. The third lens group is moved along the optical axis, toward an image side to focus from a focused state at infinity to a focused state at a minimum object distance.

Abstract: A telephoto-type imaging lens for short-distance imaging which realizes well focused image with a simple structure through the miniaturization and weight reduction of a focusing lens group, reduction of the load on a drive system for focusing and compact structure of the entire optical system; and an imaging device. The imaging lens includes a first lens group having positive refracting power, a second lens group having negative refracting power and a third lens group having positive refracting power are disposed in order from the object side, wherein at least one positive lens constitutes the second lens group, the first lens group and the third lens group are fixed and the second lens group moves to a focusing side in focusing from infinity to a close object.

Abstract: A fixed focus lens comprising, sequentially from an object side, a first lens group having a positive refractive power; a second lens group having a negative refractive power; and a third lens group having a positive refractive power. The first lens group includes an aperture stop. The second lens group is configured by a single lens element. During focusing, the second lens group moves along an optical axis and the first lens group and the third lens group are fixed with respect to an imaging plane.