Provided an imaging apparatus including a first optical device, a second optical device disposed such that light transmitted through the first optical device is incident on the second optical device, and a third optical device disposed such that light transmitted through the second optical device is incident on the third optical device, wherein at least one of the first optical device, the second optical device, and the third optical device includes a plurality of nanostructures, and heights of at least two nanostructures of the plurality of nanostructures are different from each other.

Provided an imaging apparatus including a first optical device, a second optical device disposed such that light transmitted through the first optical device is incident on the second optical device, and a third optical device disposed such that light transmitted through the second optical device is incident on the third optical device, wherein at least one of the first optical device, the second optical device, and the third optical device includes a plurality of nanostructures, and heights of at least two nanostructures of the plurality of nanostructures are different from each other.

In an optical system which includes a positive lens Gp and in which a distance on an optical axis from an object-side lens surface of a lens disposed closest to an object side to an image surface is shorter than a focal length of an entire system, an arrangement and a material of the positive lens Gp, and an arrangement of a focus unit are set appropriately.

In an optical system which includes a positive lens Gp and in which a distance on an optical axis from an object-side lens surface of a lens disposed closest to an object side to an image surface is shorter than a focal length of an entire system, an arrangement and a material of the positive lens Gp, and an arrangement of a focus unit are set appropriately.

The objective includes a first lens group having positive power and a second lens group having negative power and including a pair of meniscus lens components having concave surfaces facing each other. The first lens group includes a first lens situated closest to an object side and has positive power with a concave surface facing the object side. The objective includes three or more cemented lenses arranged closer to the object side than the pair of meniscus lens components, and satisfies the following conditional expressions.

2.6≤φ.sub.L1/D.sub.L1≤16  (1)

0.1≤|R.sub.212|/f≤3.5  (2)

Here, φ.sub.L1 and D.sub.L1 are an outer diameter and a thickness of the first lens. R.sub.212 is a radius of curvature of a surface closest to the image side in a first meniscus lens component among the pair of meniscus lens components. f is a focal length of the objective.

The objective includes a first lens group having positive power and a second lens group having negative power and including a pair of meniscus lens components having concave surfaces facing each other. The first lens group includes a first lens situated closest to an object side and has positive power with a concave surface facing the object side. The objective includes three or more cemented lenses arranged closer to the object side than the pair of meniscus lens components, and satisfies the following conditional expressions.

2.6≤φ.sub.L1/D.sub.L1≤16  (1)

0.1≤|R.sub.212|/f≤3.5  (2)

Here, φ.sub.L1 and D.sub.L1 are an outer diameter and a thickness of the first lens. R.sub.212 is a radius of curvature of a surface closest to the image side in a first meniscus lens component among the pair of meniscus lens components. f is a focal length of the objective.

An optical lens assembly includes an optical lens and a Pancharatnam Berry Phase (“PBP”) element coupled to the optical lens. The PBP element is configured to provide chromatic aberration correction for the optical lens. An Abbe number of the PBP element and an Abbe number of the optical lens have opposite signs.

An optical system includes, in order from an object side toward an image side, a first lens unit having positive refractive power, and a second lens unit having negative refractive power. A distance between consecutive ones of the lens units changes when focusing is performed. The first lens unit is stationary during focusing. The second lens unit is moved toward the image side when focus is changed from an object at infinity to an object at a short distance. Lateral magnification β2 of the second lens unit when focusing on the object at infinity, focal length f1 of the first lens unit, and focal length f2 of the second lens unit are set appropriately to satisfy predetermined mathematical conditions.

An optical system includes, in order from an object side toward an image side, a first lens unit having positive refractive power, and a second lens unit having negative refractive power. A distance between consecutive ones of the lens units changes when focusing is performed. The first lens unit is stationary during focusing. The second lens unit is moved toward the image side when focus is changed from an object at infinity to an object at a short distance. Lateral magnification β2 of the second lens unit when focusing on the object at infinity, focal length f1 of the first lens unit, and focal length f2 of the second lens unit are set appropriately to satisfy predetermined mathematical conditions.

An ultra-small camera module with wide field of view includes (a) a wafer-level lens system for forming, on an image plane, an image of a wide field-of-view scene, wherein the wafer-level lens system includes (i) a distal planar surface positioned closest to the scene and no more than 2.5 millimeters away from the image plane in direction along optical axis of the wafer-level lens system, and (ii) a plurality of lens elements optically coupled in series along the optical axis, each of the lens elements having a curved surface, and (b) an image sensor mechanically coupled to the wafer-level lens system and including a rectangular array of photosensitive pixels, positioned at the image plane, for capturing the image, wherein cross section of the ultra-small camera module, orthogonal to the optical axis, is rectangular with side lengths no greater than 1.5 millimeters.