PURPOSE: To obtain a zoom lens which is compact and also has a high variable power by setting the first lens group to a state focused to a limited distance object at the wide angle side, moving at least the second lens group to the image surface side, and executing the second variable power.
CONSTITUTION: I , II, and W, T, and ranges C, B denote the first and the second lens groups of negative and positive refractive powers, respectively, a zoom position of a wide angle end and a telephoto end, and a zoom position of a superwide angle end which has executed further a variable power to the wide angle end from a wide angle end W or WW, respectively, and the first and the second variable power ranges, respectively. Focusing is executed to a short distance object by feeding out the lens group I within the range indicated by a range A from a zoom position W (it will do that it is at the wide angle side) of the wide angle end. Subsequently, when executing the second variable power further to the wide angle side from the zoom position of the wide angle end W, a variable power to the superwide angle end WW is executed by fixing the first lens group I and moving only the second lens group II by a range B to the image surface side. In such a case, however, the focused short distance object is varied, and for instance, it is varied to a position of infinity. When it is varied to the infinity position, the depth of field goes to deep, therefore, a good image is obtained over a wide range.
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TAKAHASHI SADATOSHI
IKEMORI KEIJI
KITAGISHI NOZOMI
TANAKA TSUNEFUMI
MOMIYAMA KIKUO
