Two-group zoom lens

A zoom lens formed of only two lens groups, arranged along an optical axis in order from the object side as follows:

• a first lens group;
• and
• a second lens group;
• wherein
• the first lens group includes, arranged along the optical axis in order from the object side, a first lens component made of plastic, having negative refractive power, and having at least one aspheric lens surface, and a second lens component having positive refractive power;
• the second lens group includes, in order from the object side:
• a stop;
• a first lens component consisting of a first lens element with a biconvex shape that is made of plastic and has at least one aspheric lens surface;
• and a second lens component that includes, in order from the object side, a lens element of negative refractive power with the absolute value of the curvature of its object-side lens surface being smaller than the absolute value of the curvature of its image-side lens surface, said lens element being joined at said image-side lens surface to a lens element having a biconvex shape;
• focusing is performed by movement of the second lens group along the optical axis;
• and
• the following conditions are satisfied:
• B1/2<fG2/fw<0.9·B −2.0<fG1−1/fW<−1.5 RG2−1/fW>0.8 |fW/R1 |<0.08 10<|fG2−2,3/fW|<100
• where
• B is the zoom ratio of the zoom lens, namely, the ratio of the focal length at the telephoto end divided by the focal length at the wide-angle end,
• fG2 is the focal length of the second lens group,
• fw is the focal length of the zoom lens at the wide-angle end,
• fG1−1 is the focal length of the first lens component of the first lens group,
• RG2−1 is the radius of curvature of the object-side lens surface of the first lens element of the second lens group,
• R1 is the radius of curvature of the object-side lens surface of the first lens component of the first lens group, and
• fG2−2,3 is the composite focal length of the joined lens elements of the second lens group.