Patent ID: 9584708
Date: 2017-02-28
CPC Classifications: G02B

Claim:
1. An optical system having at least a first mode that focuses within a range of focus from an infinite object to a first close object and a second mode that focuses within a range of focus from a second close object to a third close object, the second close object being closer to an imaging apparatus than the infinite object, the third close object being closer to the imaging apparatus than the first close object, the optical system comprising: a focus lens group that is made up of one or two lenses and moves in an optical axis direction in focusing in each of the first mode and the second mode; and one or more mode change lens groups that move in the optical axis direction separately from the focus lens group when the focusing is changed from the first mode to the second mode, wherein where dA is a distance on the optical axis between an incoming plane and an outgoing plane of the focus lens group, and dB is a distance on the optical axis between an incoming plane closest to an object side among incoming planes of all lens groups that move when the focusing is changed from the first mode to the second mode and an outgoing plane closest to an image side among outgoing planes of the all lens groups, dB being a maximum distance if the distance is variable.