| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens having a high variable power ratio where aspherical plastic lens is effectively utilized by eliminating trouble such as the positional fluctuation in an image point by the characteristic change (refractive index change or volume change) of plastic material when temperature and humidity are changed. SOLUTION: This zoom lens 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 order from an object side, and variable power is performed by changing a distance between the respective lens groups. The 3rd lens group G3 is constituted of a 3m-th plastic lens in meniscus shape having an aspherical surface and turning a concave surface to the object side, a 3p-th positive lens turning a convex surface to an image side and a 3n-th negative lens arranged nearest to the image side and turning a concave surface to the object side.
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