| 摘要 |
<p>A zoom lens having a stabilized optical quality achieved by suppressing the influence of the assembly error at the time of its manufacture. A positive first lens group (G1), a negative second lens group (G2), a positive third lens group (G3), and a positive fourth lens group (G4) are arranged sequentially from the object side. The lens groups (G1, G3) are fixed, and the lens group (G2) is moved toward the image side when the zoom lens changes from its wide angle end state to its telescope end state. The variation of the image plane position incident to the movement of the lens group (G2) is compensated through the movement of the lens group (G4). An aperture stop (S) is fixed to the object side of the lens group (G3). The lens group (G2) is constituted of a negative meniscus lens (L21) having a concave surface facing the image side and a cemented lens (L22) composed of a double-concave lens and a positive lens having a convex surface facing the object side, arranged sequentially from the object side. The negative meniscus lens is a compound lens where a resin lens (PL) provided to the image side of a glass lens, and the resin lens has an aspherical surface facing the object side and satisfies the following condition (1). (1) n2>1.75 where n2 is the average refractive index of the glass forming the lens group (G2).</p> |
