| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens having an almost double magnification ratio and a full length almost as long as a four-times focal distance at a wide angle end by satisfying specified conditions for the focal distance of a lens group or the like. SOLUTION: This lens is provided with a first lens group G1 having negative refraction power, second lens group G2 having positive refraction power, and third lens group G3 having positive refraction power. The first lens group G1 is composed of only one biconcave lens. In the case of magnification from wide angle end to telescopic end, a gap between the first lens group G1. and the second lens group G2 is decreased and a gap between the second lens group G2 and the third lens group G3 is increased. When the focal distance of the first lens group G1 is defined as f1, the focal distance of the second lens group G2 is defined as f2, the focal distance of the third lens group G3 is defined as f3 and a distance from the surface of the lens on the most object side of the zoom lens at the wide angle end to an image surface along with an optical axis is defined as TLω, this lens is constituted so as to satisfy the conditions of 0.4<|f1|/TLω<0.8 and 0.8<f3/f2<1.6.
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