| 摘要 |
<p>Disclosed is an image pickup optical system (1) which is sequentially provided with, from the object side to the image side: a first lens group (LG1), which is composed of at least two lenses, including a positive lens (first lens (L1)) disposed closest to the object, and has positive refractive power as a whole; a second lens group (LG2), which is composed of at least one lens, and has positive refractive power as a whole; and a third lens group (LG3), which is composed of at least one lens. The first lens group (LG1) and the third lens group (LG3) are fixed to an image pickup surface (70a), the second lens group (LG2) is provided movably in the optical axis direction for the purpose of focus adjustment, and the image pickup optical system (1) satisfies the conditional expression of 0.1<f1/fg2<2, where f1 is the focal point distance of the positive lens closest to the object, fg2 is the focal point distance of the second lens group.</p> |
