| 摘要 |
<p>Provided is an image pickup optical system configured from three lenses and having optical properties, such as aberration, peripheral light amount ratio, and brightness, equal to or higher than those of an image pickup optical system configured from four lenses. Specifically provided is an image pickup optical system which comprises, from the object side to the image side, a positive first lens with a diffraction grating on the image side, a second lens that is a meniscus lens with a convex surface directed to the image side, and a third lens that is a negative meniscus lens, and in which a stop is disposed closer to the object side than the surface on the image side of the first lens. The image pickup optical system satisfies the following expressions: 0.18<D12×f<0.22 (1) 1.1<TTL×f<1.22 (2) Fno<3.0 (3) 0.46<r1×f<0.49 (4) 0.8<f/f1<1.0 (5) |f2/f|<0.1 (6) Where D12 is the distance on the optical axis between the first lens and the second lens, TTL is the distance from the vertex on the object side of the first lens to the image surface, f1 is the power of the first lens, f2 is the power of the second lens, f is the combined power of the first lens, the second lens, and the third lens, Fno is the f-number of the optical system, and r1 is the curvature radius of the surface on the object side of the first lens.</p> |
