| 摘要 |
PROBLEM TO BE SOLVED: To shorten the entire length of a lens system, to excellently compensate aberration and to make a telephoto ratio small by constituting the lens of four lens groups, moving the respective lens groups to an object side and moving them so that a distance between the specified lens groups may be large or small at the time of varying power and satisfying a specified conditional expression. SOLUTION: This zoom lens is constituted of four lens groups G1 to G4 and the respective lens groups G1 to G4 are moved to the object side and moved so that the distance between the 1st and the 2nd lens groups G1 and G2 may be large and the distance between the 3rd and the 4th lens groups G3 and G4 may be small at the time of varying power. Then, it satisfies the conditional expressions (1) 0.02<|f4|/fr<0.3, (2) 0.1<ΔX4T/fr<0.5 and (3) 1.5<β4T/β4W<6.0. Provided that f4 is the focal distance of the 4th lens group G4, fr is the focal distance of an entire system at a telephoto end,ΔX4T is the zooming moving amount of the 4th lens group G4 to the telephoto end when a wide-angle end is set as reference,β4T is the lateral magnification of the 4th lens group G4 at the telephoto end andβ4W is the lateral magnification of the 4th lens group G4 at the wide-angle end.
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