To provide a single focus lens that sufficiently satisfies a demand for the entire length of an optical system, a demand for high image quality and a demand for a low cost.
The single focus lens includes, in order from the object side: a meniscus-shaped first lens of positive power, the object side face of which is convex; and a second lens that is aspherical on both sides such that its shape near the center is convex on the object side and has positive power, and the shape of the peripheral part is concave on the object side and has negative power following the gradual decrease in positive power toward the periphery. The single focus lens satisfies conditional expressions: (1) 1.65L/Ih1.89; and (2) 0.88|h1/h2|; wherein L is the entire length of the optical system; Ih is the radii of an image circle; h1 is the height of the inflection point of the object side face of the second lens from an optical axis; and h2 is the height of the inflection point of the image side face of the second lens from the optical axis.
| JP2004258310 | WIDE ANGLE LENS EQUIPPED WITH GRADIENT INDEX LENS |
| WO/2018/163831 | LENS SYSTEM, INTERCHANGEABLE LENS DEVICE, AND CAMERA SYSTEM |
| JPH1165033 | FILM UNIT WITH LENS |
Toru Yui
Hitoshi Kiyono
Fukuoka Masahiro