| 摘要 |
An imaging optical system includes a front lens group including a front lens element and a reflector element which reflects a light bundle that exits from the front lens element; and a rear lens group on the image side of the front lens group. The front lens element is a spherically-swingable lens group which suppresses image shake by spherically-swinging about a predetermined spherical-swing center in accordance with vibrations applied to the imaging optical system. The following conditions (1) and (2) are satisfied:;νd>58 (1),;and;f/y>3 (2),;wherein νd designates the Abbe number with respect to the d-line of at least one lens element of the spherically-swingable lens group, f designates the focal length of the imaging optical system, in a state where the focal length is at a maximum, and y designates the maximum image height of the imaging plane. |
| 主权项 |
1. An imaging optical system comprising:
a front lens group including at least one front lens element, and a reflector element which reflects a light bundle that exits from said front lens element, in that order from the object side; and a rear lens group provided on the image side of said front lens group, wherein said front lens element serves as a spherically-swingable lens group which, in an image-stabilizing operation, suppresses image shake on the imaging plane by spherically-swinging said spherically-swingable lens group about a predetermined spherical-swing center in accordance with vibrations applied to said imaging optical system, and wherein the following conditions (1) and (2) are satisfied:
νd>58 (1),andf/y>3 (2),wherein
νd designates the Abbe number with respect to the d-line of at least one lens element of said spherically-swingable lens group; f designates the focal length of said imaging optical system, in a state where the focal length is at a maximum; and y designates the maximum image height of the imaging plane. |
