| 摘要 |
A compact two-group zoom lens, wherein zooming is accomplished by changing the distance between the two lens groups. In order from the object side, the first lens group G1 is of positive refracting power and includes a negative meniscus lens element L1 with its concave surface on the object side, a positive meniscus lens element L2 made of plastic having two aspherical surfaces with its convex surface on the object side, and a biconvex lens element L3 having different surface curvatures, with its surface of stronger curvature on the image side. The second lens group G2 includes a positive meniscus lens element L4 that has two aspherical surfaces with its concave surface on the object side, and a negative meniscus lens element L5 with its concave surface on the object side. It is preferable that lens element L4 has an aspherical surface of positive refracting power and lens element L2 has an aspherical surface of negative refracting power. Also, it is preferable that lens elements L2 and L4 are formed with an acrylic-system resin. Furthermore, the following conditions are satisfied: 1.4<fw/f1<2.0 (1) -0.77<R9/f1<-0.35 (2) wherein fw is the focal length of the compact two-group zoom lens at the wide-angle end, f1 is the focal length of the first lens group, and R9 is the radius of curvature of the object-side surface of the fifth lens element.
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