Zoom lens
A zoom lens includes, sequentially from an object side, a first lens group that is negative; and a second lens group that is positive, where focal length is varied by varying a distance between the first lens group and the second lens group. The first lens group includes, from the object side, a first lens that is a negative biconcave lens having at least one aspherical surface, and a second lens that is a positive meniscus lens having a convex surface facing toward the object side and at least one aspherical surface, and a first condition 0.8<|f 1 /f 2 |<1.0 and a second condition 0.5<|r 2 /f 1 |<0.8 are satisfied, where f 1 is the focal length of the first lens group, f 2 is the focal length of the second lens group, r 2 is radius of curvature of a surface of the first lens in the first lens group, the surface facing toward an image.
1. A zoom lens comprising, sequentially from an object side:
a first lens group that is negative; and
a second lens group that is positive, wherein
focal length is varied by varying a distance between the first lens group and the second lens group,
the first lens group includes, from the object side, a first lens that is a negative biconcave lens having at least one aspherical surface, and a second lens that is a positive meniscus lens having a convex surface facing toward the object side and at least one aspherical surface, and
a first condition 0.8<|f 1 /f 2 |<1.0 and a second condition 0.5<|r 2 /f 1 |<0.8 are satisfied, f 1 being a focal length of the first lens group, f 2 being a focal length of the second lens group, r 2 being radius of curvature of a surface of the first lens in the first lens group, the surface facing toward an image.
2. The zoom lens according to claim 1 , wherein
the second lens group includes, sequentially from the object side, a first lens that is positive and has at least one aspherical surface, a second lens that is negative and has at least one aspherical surface, a third lens that is positive, and a fourth lens that is negative,
the third lens and the fourth lens are cemented to each other, and
a third condition |(1/f 21 )+(1/f 22 )|×f w <0.1 is satisfied, f 21 being a focal length of the first lens in the second lens group, f 22 being a focal length of the second lens in the second lens group, f w being a focal length occurring at a wide angle edge of the zoom lens.
3. The zoom lens according to claim 2 , wherein
a fourth condition υd 24 <26 is satisfied, υd 24 being an Abbe number with respect to a d line of the fourth lens in the second lens group.
4. The zoom lens according to claim 2 , wherein
the first lens and the second lens of the second lens group are formed of resin.
5. The zoom lens according to claim 1 , wherein
the first lens and the second lens of the first lens group are formed of resin.
6. The zoom lens according to claim 5 , wherein
the first lens and the second lens of the second lens group are made of resin.