| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens which has a wide view angle and a high power variation ratio and is composed of the small number of constituent elements and is reducible in cost by providing a 1st lens group with negative refracting power and a 2nd lens group with positive refracting power and satisfying specific conditions. SOLUTION: This zoom lens is equipped with the 1st lens group G1 with the negative refracting power and the 2nd lens group G2 with the positive refracting power in order from an object side, and is varied in power by varying the air space between the lens groups G1 and G2 . The 1st lens group G1 has a 1st-lens-group 1st lens element L11 which is formed in a meniscus shape concave to the image side and has negative refracting power and meets respective conditions of 1.0<|f1|/fw <2.0, 1.5<f2 /fw <3.5, and 0.5<|f11|/fw <4. In the inequalities, f1 is the focal length of the 1st lens group G1 and f2 is the focal length of the 2nd lens group G2 . Further, fw is the focal length of the whole system at a wide-angle end and f11 is the focal length of the 1st lens element L11 of the 1st lens group.
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