PROBLEM TO BE SOLVED: To provide a compact optical system and an image pickup apparatus having high optical performance regardless of an object distance while realizing high-speed focusing.
[0002] In recent years, small image pickup devices using solid-state image pickup elements such as digital still cameras have become remarkably widespread. Along with this, there is a demand for higher performance and smaller optical systems. In addition, it is possible to suppress aberration fluctuations during focusing, especially deterioration of spherical aberration and curvature of field during focusing from an infinity object to a short-distance object, and maintain high optical performance regardless of the object distance. It has been demanded.
[0003] For example, in Patent Document 1, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the positive refractive power arranged in order from the object side are described in Patent Document 1. It consists of a third lens group, a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power. An optical system that focuses by moving the fourth lens group to the object side with different trajectories has been proposed.
[0005] That is, in the optical system of Patent Document 1, a focusing method based on an inner focus method having a so-called floating mechanism is adopted. The optical system disclosed in Patent Document 1 realizes high-speed focusing and suppresses aberration fluctuations during focusing to obtain high optical performance. However, the diameter of each focusing group is relatively large, and the product The overall miniaturization is not enough.
[0006] Therefore, an object of the present invention is to provide a compact optical system and an image pickup apparatus having high optical performance regardless of an object distance while realizing high-speed focusing.