Fuji Photo Optical Co., Ltd.

Eiichi Kabe

Yasunobu Sakaguchi

Tomonori Nishio

A lens apparatus includes four lens groups and a plurality of barrels with grooves that guide and drive the lens frames of the four lens groups in order to achieve a high zoom ratio and retraction of the lens apparatus into a camera body when the lens apparatus is not in use. Two sets of three guide grooves in a fixed barrel and three cam grooves in a cam barrel are unequally spaced around the circumference of the barrels so as to provide more room for an additional groove in the cam barrel. Some of the lens frames are fully supported by pins in the grooves and some of the lens frames are partially supported by guide rods in the lens apparatus. A single guide rod helps support two lens frames in order to save space in the lens apparatus.

Lens apparatus

A method and mechanism are disclosed for driving optical members in an optical apparatus, in which cam means formed on a lens barrel are provided with insensitive zones, so that the lens barrel is rotated to drive a diaphragm for adjustment of its diaphragm stop after the lens has been moved to the insensitive zones, then the lens barrel is rotated in the reverse direction with the diaphragm being maintained at its adjusted diaphragm stop, and thereby power variation and/or focussing of the lens as well as adjustment of the diaphragm stop are achieved using a single drive source. A cylindrical cam 40 is provided within a stationary lens barrel 30 so as to be rotatable around an optical axis S. The cylindrical cam 40 is formed with cam slits 41 each having insensitive zones 42 at longitudinally opposite ends thereof so that an enlarging lens 20 can not be further moved back and forth when lens driving pins 27 lie in these insensitive zones 42. Diaphragm driving plates 43, 44 are mounted on the inner wall of the cylindrical cam 40 so that rotation of the cylindrical cam 40 causes these diaphragm driving plates 43, 44 to drive the diaphragm driving pin 24 while the lens driving pins 27 lie in the insensitive zones 42 and thereby to vary a diaphragm stop of an iris diaphragm 22. Once the diaphragm stop has been varied, the cylindrical cam 40 is rotated in the reverse direction to move the enlarging lens 20 to a desired position for desired power variation and/or focussing.

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Saitama, Japan

Eiichi Kabe