| 摘要 |
PURPOSE:To obtain a distance information of an object from a counting value corresponding to a momentum extending from a prescribed initial position of a lens driving mechanism to focusing, and a prescribed coefficient from an interchangeable lens side by generating a pulse in accordance with said mechanism provided on a camera side. CONSTITUTION:When a mount part of an interchangeable lens is fitted into an opening of a bayonet seat plate 46, a connecting shaft 42 is connected to a shaft to be moved 60. When a motor shaft 2 is controlled and rotated by an automatic focus controlling circuit, lenses 72, 74 are moved forward and backward through a helicoid gear 68a from a friction gear 6 and an intermediate gear 10, and at the same time, an encoder plate 18 is rotated, and a pulse signal of a number corresponding to the rotational amount of the encoder plate 18 is outputted by a photocoupler 24. Basing on this signal, a counting value corresponding to a momentum extending from a prescribed initial position of a lens driving mechanism to focusing is derived by a circuit, and a distance information to an object is obtained from said value and a prescribed coefficient from the interchangeable lens side. |
