| 摘要 |
PROBLEM TO BE SOLVED: To obtain a variable magnification optical system by which a still picture is obtained by optically correcting the blurring of a photographic picture when the variable magnification optical system is vibrated and which possesses a vibration-proof function. SOLUTION: This is the variable magnification optical system orderly having a first lens group L1 of positive refracting power, the second lens group L2 of negative refracting power, the third lens group L3 of positive refracting power and then the fourth lens group L4 of positive refracting power from an object side. In this case, variable magnification is executed by moving the first, second and fourth lens groups L1, L2 and L4 in an optical axis direction, and focusing is executed by moving the fourth lens group L4 in the optical axis direction, and the blurring of the photographic picture when the variable magnification optical system is vibrated is corrected by moving the whole third lens group L3 in the direction perpendicular to an optical axis, and the first lens group L1 possesses a meniscus negative lens having a concave surface on an image surface side on the most object side, and the second lens group L2 possesses the meniscus negative lens having the concave surface on the image surface side on the most object side, so that the moving quantities m1 and m2 of the first lens group L1 and the second lens group L2 required for the variable magnification from a wide angle end to the telephoto end are respectively appropriately set.
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