| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which is made small in size and light in weight and has high specification and high performance. SOLUTION: This zoom lens is constituted of four lens groups, that is, a 1st lens group G1 fixed in the midst of zooming and having positive refractive power, 2nd and 3rd lens groups G2 . and G3 movable in the case of zooming and having negative refractive power, and a 4th lens group G4 fixed in the midst of zooming and having the positive refractive power in order from an object side; and the 4th lens group G4 is constituted of at least six lens groups. Assuming that fT is the composite focal length of an entire system at a telephoto end, FT is an f-number at the telephoto end, f1 is the focal length of the 1st lens group G1 ,βZW, is the magnification of the 2nd lens group G2 at a wide angle end, V is zoom ratio, A4 is the maximum distance in the 4th lens group G4 , D4 is a distance to a lens surface most proximate to an image side from a lens surface most proximate to the object side in the 4th lens group G4 , the respective conditions that 0.7<(FT)<1/2> .f1 /f1 <1.1, 1.1<|β2 W.V<1/2> <1.5, and A4 /D4 <0.15 are satisfied.
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