| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens that has superior performance and a small lens diameter, to provide an optical apparatus having the zoom lens, and to provide a method of manufacturing the zoom lens. SOLUTION: The zoom lens includes, in order from an object side, a first lens group G1 of negative refractive power, a second lens group G2 of positive refractive power, and a third lens group G3 of positive refractive power. To zoom from a wide angle end to a telephoto end, at least the G1 and G2 move so as to decrease an interval between the G1 and G2 and to increase an interval between the G2 and G3. The G3 is composed of a single positive lens. If the maximum image height is Ymax, the focal distance at the telephoto end is ft, the focal distance at the wide angle end is fw, the focal distance of G1 is f1, the object-side paraxial curvature radius of a positive lens composing the G3 is Ra, and the image-side paraxial curvature radius of the positive lens composing the G3 is Rb, the zoom lens satisfies conditions expressed by formulae given below: 1.7<Ymax×ft/(fw×¾f1¾)<2.3, and -0.2<(Rb+Ra)/(Rb-Ra)<1.2. COPYRIGHT: (C)2011,JPO&INPIT |
