US 7,542,216 B2
Zoom lens system
Katsuhiko Nishikawa, Saitama (Japan); and Noriyuki Nakazawa, Saitama (Japan)
Assigned to Tamron Co., Ltd., Saitama-shi, Saitama (Japan)
Filed on Aug. 14, 2008, as Appl. No. 12/222,702.
Claims priority of application No. 2007-239436 (JP), filed on Sep. 14, 2007.
Prior Publication US 2009/0073576 A1, Mar. 19, 2009
Int. Cl. G02B 15/14 (2006.01)
U.S. Cl. 359—700  [359/701; 396/72] 4 Claims
OG exemplary drawing
 
1. A zoom lens system comprising a first cam barrel rotating about an optical axis of the system and a second cam barrel located inside the first cam barrel in cam-linkage with the same,
the second cam barrel including openings to let light beams pass through,
a light-shielding plate like an iris diaphragm being supported by the second cam barrel in position closer to photographed subject in the second cam barrel so as to shield the light beams that come in from the openings in the second cam barrel after going out of the openings in the second cam barrel and then being reflected from an inner surface of the first cam barrel.