A rear attachment lens according to the aspect of the embodiments is configured to vary a focal length of a system by being attached to an image side of a master lens. The rear attachment lens includes a positive lens arranged closest to the image side in which a lens surface on the image side of the positive lens has a shape convex toward the image side. A focal length of the rear attachment lens, a magnification of the rear attachment lens when attached to the master lens, and a distance from the lens surface on the image side of the positive lens to a rear principal point position of the rear attachment lens when attached to the master lens are appropriately set.

A rear attachment lens according to the aspect of the embodiments is configured to vary a focal length of a system by being attached to an image side of a master lens. The rear attachment lens includes a positive lens arranged closest to the image side in which a lens surface on the image side of the positive lens has a shape convex toward the image side. A focal length of the rear attachment lens, a magnification of the rear attachment lens when attached to the master lens, and a distance from the lens surface on the image side of the positive lens to a rear principal point position of the rear attachment lens when attached to the master lens are appropriately set.

A mirror unit 2 includes a mirror device 20 including a base 21 and a movable mirror 22, an optical function member 13, and a fixed mirror 16 that is disposed on a side opposite to the mirror device 20 with respect to the optical function member 13. The mirror device 20 is provided with a light passage portion 24 that constitutes a first portion of an optical path between the beam splitter unit 3 and the fixed mirror 16. The optical function member 13 is provided with a light transmitting portion 14 that constitutes a second portion of the optical path between the beam splitter unit 3 and the fixed mirror 16. A second surface 21b of the base 21 and a third surface 13a of the optical function member 13 are joined to each other.

An imaging optical lens assembly includes an aperture stop and a plurality of lens elements. The aperture stop has a fixed elliptical shape, and the aperture stop has a major axis and a minor axis.

An imaging optical system according to the present disclosure includes: a lens; and an optical member, in which the optical member is configured such that a light transmittance value at least in a peripheral portion is larger than a light transmittance value in a central portion. Furthermore, a camera module according to the present disclosure includes the imaging optical system of the present disclosure. Furthermore, an electronic device according to the present disclosure includes a solid-state imaging element and the imaging optical system of the present disclosure.

An imaging optical system according to the present disclosure includes: a lens; and an optical member, in which the optical member is configured such that a light transmittance value at least in a peripheral portion is larger than a light transmittance value in a central portion. Furthermore, a camera module according to the present disclosure includes the imaging optical system of the present disclosure. Furthermore, an electronic device according to the present disclosure includes a solid-state imaging element and the imaging optical system of the present disclosure.

An optical arrangement is provided. The optical arrangement has a center axis, an object side, an image side, and a catadioptric arrangement. The optical arrangement has an installation space of no more than 25 millimeters from the object side to the image side along the center axis, and a linear obscuration of no more than 60 percent.

An optical arrangement is provided. The optical arrangement has a center axis, an object side, an image side, and a catadioptric arrangement. The optical arrangement has an installation space of no more than 25 millimeters from the object side to the image side along the center axis, and a linear obscuration of no more than 60 percent.

The present disclosure discloses an optical imaging lens assembly, and the optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis: a first lens having positive refractive power, and at least one subsequent lens having refractive power. An F-number Fno1 of the optical imaging lens assembly satisfies Fno1>3.5, where an object distance is finite, and an F-number Fno2 of the optical imaging lens assembly satisfies Fno21.0, where the object distance is infinite.

The present disclosure discloses an optical imaging lens assembly, and the optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis: a first lens having positive refractive power, and at least one subsequent lens having refractive power. An F-number Fno1 of the optical imaging lens assembly satisfies Fno1>3.5, where an object distance is finite, and an F-number Fno2 of the optical imaging lens assembly satisfies Fno21.0, where the object distance is infinite.