| 摘要 |
A zoom lens system consists, in order from an object side to an image-forming side, of a first negative lens group G1, a second positive lens group G2, and a third positive lens group G3. The first lens group G1 consists of one negative lens and one positive lens, the second lens group G2 consists of a cemented lens composed of a positive lens and a negative lens, and one meniscus lens that is concave on the image-forming side, the third lens group G3 consists of a single positive lens, and a combined focal length f2 of the second lens group, a focal length Lf23 of the meniscus lens of the second lens group, a combined focal length fw of the zoom lens system at a wide angle end, a combined focal length f3 of the third lens group, a radius of curvature Ro of an object side surface of the positive lens in the cemented lens, and a radius of curvature Ri of an image-forming side surface of the positive lens in the cemented lens satisfy the following conditions. <?in-line-formulae description="In-line Formulae" end="lead"?>0<|f2/Lf23|<0.3<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>-2.0<Ri/Ro<-1.0<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.25<fw/f3<0.45<?in-line-formulae description="In-line Formulae" end="tail"?>
|
