Abstract: The zoom lens 100 comprises, sequentially from the object side, a stationary first lens group 110 having positive refractive power; a second lens group 120, having negative refractive power, and that moves on the optical axis when changing the magnification; a stationary third lens group 130 that has positive refractive power; and a fourth lens group 140, having positive refractive power. The first lens group 110 comprises six lenses. The second lens L2 is a meniscus lens that is formed so as to have at least one aspherical surface. The aspherical surface of the second lens L2 is formed at the shape wherein there is no displacement in the thickness from the center portion to the edge portion. Doing so enables the effective correction of distortion and off-axis aberration on the wide-angle side, and the provision of a high-performance zoom lens that is small and has a high variable magnification.

Abstract: The zoom lens 100 comprises, sequentially from the object side, a stationary first lens group 110 having positive refractive power; a second lens group 120, having negative refractive power, and that moves on the optical axis when changing the magnification; a stationary third lens group 130 that has positive refractive power; and a fourth lens group 140, having positive refractive power. The first lens group 110 comprises six lenses. The second lens L2 is a meniscus lens that is formed so as to have at least one aspherical surface. The aspherical surface of the second lens L2 is formed at the shape wherein there is no displacement in the thickness from the center portion to the edge portion. Doing so enables the effective correction of distortion and off-axis aberration on the wide-angle side, and the provision of a high-performance zoom lens that is small and has a high variable magnification.

Abstract: To provide a technique to constitute a fisheye lens unit with a small number of lenses. A fisheye lens unit uses a predetermined projection method, wherein a variation for the predetermined projection method is not less than the variation for an equidistant projection method, the variation being expressed by an increment of an image height in relation to an increment of an incident angle at a predetermined incident angle. The fisheye lens unit includes: a first lens group provided on an object side; a second lens group provided on an image side; and an aperture stop provided between the first lens group and the second lens group. The first lens group consists of three or four lenses, the second lens group consists of two or three lenses including a final lens provided on the furthest image side of the second lens group, and the final lens is an aspheric lens that has an aspheric shape on at least one of two surfaces of the aspheric lens.

Abstract: To provide a technique to constitute a fisheye lens unit with a small number of lenses. A fisheye lens unit uses a predetermined projection method, wherein a variation for the predetermined projection method is not less than the variation for an equidistant projection method, the variation being expressed by an increment of an image height in relation to an increment of an incident angle at a predetermined incident angle. The fisheye lens unit includes: a first lens group provided on an object side; a second lens group provided on an image side; and an aperture stop provided between the first lens group and the second lens group. The first lens group consists of three or four lenses, the second lens group consists of two or three lenses including a final lens provided on the furthest image side of the second lens group, and the final lens is an aspheric lens that has an aspheric shape on at least one of two surfaces of the aspheric lens.