| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which is wide-angle with a half view angle of 42 degrees at a short focal length end, has a low F-number and a number of constituent lenses as low as 12 or so, is compact, and offers high resolving power compatible with image sensors with 10 to 20 million pixels.SOLUTION: A zoom lens includes 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 arranged in order from the object side. The first lens group G1 comprises a positive lens L10 and the second lens group G2 comprises a negative lens L21 having a concave surface on the image side, a negative lens L22 having a concave surface on the image side, a negative lens L23 having a concave surface on the object side, and a positive lens L24 having a convex surface on the object side arranged in order from the object side. A focal length f2_3 of the negative lens L23 of the second lens group G2 and a focal length f2 of the entire second lens group G2 satisfy the following conditional expression [1]: 1.5<f2_3/f2<2.5...[1]. |
