| 摘要 |
PROBLEM TO BE SOLVED: To obtain a variable focal length lens system which is compact and suitable for high variable power by constituting the variable focal length lens system to satisfy a specified condition. SOLUTION: This lens system is constituted of a 1st lens group G1 having positive refractive power, a 2nd lens group G2 having positive refractive power and a 3rd lens group G3 having negative refractive power in this order from the object side. The 1st lens group G1 to the 3rd lens group G3 are all moved to the object side so that a distance between the 1st and the 2nd lens groups G1 and G2 may be increased and a distance between the 2nd and the 3rd lens groups G2 and G3 may be decreased. When it is assumed that the lateral magnification of the negative lens group G3 in a wide angle end state isβwb, the focal length of a negative lens L32 in the negative lens group G3 is (fn), the focal length of a positive lens L31 in the negative lens group G3 is (fp) and the focal length of the negative lens group G3 is (fb), the lens system satisfies conditions 1.35<βwb<1.60 and 1.3<(|fn|+fp)/|2.fb|<2.6.
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