Patent ID: 8212898
Filing Date: 2012-07-03
Classification: G02B

Abstract:
1. A driving method for a zoom lens device, the zoom lens device comprising a lens system including a zoom group for changing a focal length of the lens system by moving in one optical axis direction during a magnification change, the zoom group including one or more lenses, and a correction group for correcting movement of an image plane by reversing a movement direction thereof during the magnification change, the correction group including one or more lenses, the method driving the zoom lens device in accordance with a table which contains zoom position data indicating respective stoppable positions of the zoom group and the correction group, wherein when a focal length of the lens system at a position at which the movement direction of the correction group is reversed is expressed as fr, and when, with zoom positions of the correction group being numbered in ascending order from a shortest focal length, a zoom position of the correction group is expressed as n, which is a natural number, and a focal length of the lens system at the zoom position n of the correction group is expressed as fn and a focal length of the lens system at a zoom position (n+1) adjacent to the zoom position n of the correction group is expressed as f(n+1), for a focal length fn and a focal length f(n+1) that satisfy a relationship of fn<fr<f(n+1), the zoom position n and the zoom position (n+1) are set such that a difference value (f(n+1)−fn) between the focal length f(n+1) and the focal length fn is larger than a difference value (f(m+1)−fm) between a focal length fm and a focal length f(m+1) of the lens system at any adjacent zoom positions m and (m+1) of the correction group other than the zoom positions n and (n+1), where m is a natural number that satisfies m≠n.