To provide a compact image pickup optical system easily securing a back focus and an imaging apparatus using the same.
The image pickup optical system is constituted of two lenses, that is, a 1st meniscus lens L1 turning its convex surface toward an object side and a 2nd lens L2 having a convex surface formed so that the absolute value of curvature on its object side surface is larger than that on its image side surface and having positive refractive power, and a brightness diaphragm S is arranged on the object side of an image forming lens part. It satisfies the following condition (1) on the ratio of the focal distances of the 1st and the 2nd lenses L1 and L2 and the following condition (2) on the shape factor of an air lens between the 1st and the 2nd lenses L1 and L2. The condition (1): -0.27<f2/f1<0.27. The condition (2): -0.5<(r2-r3)/(r2+r3)<0.2. But, in the conditions (1) and (2), f1 denotes the focal distance of the 1st lens, f2 the focal distance of the 2nd lens, r2 the radius of curvature on an optical axis of the image side surface of the 1st lens, and r3 the radius of curvature on the optical axis of the object side surface of the 2nd lens,.
| JPS6375719 | FOURIER TRANSFORMING LENS |
| WO/2021/223598 | OPTICAL LENS AND IMAGING DEVICE |
| WO/2011/124896 | OPTICAL ELEMENT WITH SUB ELEMENTS AND AN ADRESSABLE MASK |
Ryukichi Abe
Hirukawa Masanobu
Norihiko Uchida
Hideo Sugai
Kenji Aoki
Akira Yonezawa