| 摘要 |
An optical system includes, in order from an object side to an image side, a first lens unit having a positive refractive power, an aperture stop, and a rear lens group. In the optical system, the rear lens group includes a second lens unit configured to move during focusing. The first lens unit includes n positive lenses (n is an integer greater than 1) and one or more negative lenses. With an order of an optical member counted from the object side towards the image side being indicated by i (i is an integer equal to or greater than 1), a refractive index and an Abbe number of a material of an i-th positive lens of the first lens unit with respect to d-line light (Ndi, nudi), maximum and minimum values of the Abbe number nudi (max(nudi), min(nudi)), a minimum value of the refractive index Ndi (min(Ndi)), a focal length of the first lens unit (fp), and a focal length of the entire optical system (f) are appropriately set. |
