OPTICAL SYSTEM AND IMAGING APPARATUS INCLUDING THE SAME

摘要

An optical system includes a focusing lens unit configured to move in a first focusing mode intended for focusing within a range of object distances from infinity to a first finite distance and in a second focusing mode intended for focusing within a range of object distances from a second finite distance that is shorter than infinity to a third finite distance that is shorter than the first finite distance, and a mode-changing unit configured to move when the focusing mode is changed between the first focusing mode and the second focusing mode. In the optical system, lateral magnification βf of the focusing lens unit when focusing on a point at infinity, and lateral magnification βr of a combination of any lenses that are on an image side with respect to the focusing lens unit when focusing on the point at infinity are set appropriately.

主权项

1. An optical system comprising:
a focusing lens unit configured to move in a first focusing mode intended for focusing within a range of object distances from infinity to a first finite distance and in a second focusing mode intended for focusing within a range of object distances from a second finite distance that is shorter than infinity to a third finite distance that is shorter than the first finite distance; and a mode-changing unit configured to move when the focusing mode is changed between the first focusing mode and the second focusing mode, wherein the optical system satisfies the following conditional expression:
2.20<|1−βf2|×βr2<9.00where βf denotes lateral magnification of the focusing lens unit when focusing on a point at infinity, and βr denotes lateral magnification of a combination of any lenses that are on an image side with respect to the focusing lens unit when focusing on the point at infinity.