| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens of high image quality where various kinds of aberration are improved and which is the most suitable to be used for a still camera. SOLUTION: The zoom lens is constituted of a 1st lens group Gr1 to a 5th lens group Gr5 having positive, negative, positive, positive and almost zero refractive power, respectively, in order from an object side, and the 3rd lens group Gr3 is constituted of a joint lens constituted of a convex lens and a concave lens, and also, the 5th lens group Gr5 is constituted of a joint lens constituted of a concave lens and a convex lens, and provided thatν3 denotes equivalent Abbe's number of the 3rd lens group Gr3,ν5.1 denotes Abbe's number of the lens on the object side of the 5th lens group Gr5ν5.2 denotes Abbe's number of the lens on the image field side of the 5th lens group Gr5, r5.2 denotes the curvature radius of the lens joint face of the 5th lens group Gr5, fw denotes the focal distance of the whole lens system at a wide angle end, andωW denotes the half viewing angle at the wide angle end, the following conditions are satisfied; -0.018<1/ν3<0.018, 10<|ν5.1-ν5.2|and 1<|r5.2/ fW.tanω|<3.
|
