EXTREMELY COMPACT HIGH VARIABLE-POWER ZOOM LENS SYSTEM INCLUDING WIDE-ANGLE RANGE

摘要

PURPOSE:To obtain the zoom lens system which has a wide-angle - telephoto zoom range and an about X3 zoom ratio by varying the air gaps between 1st and 2nd groups and 2nd and 3rd groups and satisfying specific conditions at the time of zooming operation with positive-negative-positive three-group constitution. CONSTITUTION:The high-power zoom lens which has such a wide-angle range that the shortest focal length fs is shorter than the picture plane diagonal length LD and the longest focal length fl is =2 as long as the picture plane diagonal length LD consists of the 1st group I with positive refracting power, the 2nd group II with negative refracting power, and the 3rd group III with positive refracting power in order from the object side. Then when zooming from the shortest focal length state to the longest focal length state is performed, the 1st group I and 3rd group III are moved from the picture plane side to the object side so as to vary the air gaps between the 1st group I and 2nd group II, and the 2nd group II and 3rd group III, and inequalities are satisfied.