| 摘要 |
When rotational force of a zooming motor is transmitted to a driving gear, a main moving frame in a lens body tube is moved along an optical axis while the main moving frame is rotated. Thus, a moved frame is moved along the optical axis and a cam frame is rotated while the cam frame is moved along the optical axis. While a zooming optical system is moved from a wide angle position to a storing position, a moving frame for a second lens group is rotated by rotational force of the cam frame while the moving frame for the second lens group is moved along the optical axis. Further, a moving frame for a third lens group is moved along the optical axis while no moving frame for the third lens group is rotated. A converter lens is inserted into an optical path of an effective light beam from an escaping position by a relative rotating operation of these two moving frames. Accordingly, it is possible to provide an optical system having a super short focal length which cannot be obtained within a zooming region. When the cam frame is further rotated in the same direction, the lens body tube attains a storing state providing a shortest body tube length.
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