Zoom lens and imaging apparatus

A zoom lens, substantially consisting of:

• a first lens group having a positive refractive power, which is fixed while changing magnification;
• a second lens group having a negative refractive power, which moves from an object side to an image side while changing magnification from a wide angle end to a telephoto end;
• a third lens group having a negative refractive power, which corrects movement of an imaging surface while changing magnification;
• and
• a fourth lens group having a positive refractive power, which is fixed while changing magnification, provided in this order from the object side;
• the first lens group substantially consisting of:
• a first lens subgroup having a negative refractive power, which is fixed during focusing operations;
• a second lens subgroup having a positive refractive power, which moves during focusing operations;
• and a third lens subgroup having a positive refractive power, which is fixed during focusing operations, provided in this order from the object side;
• the second lens subgroup substantially consisting of:
• a positive lens having a surface having a radius of curvature with a smaller absolute value toward the image side;
• and a cemented lens constituted by a negative lens toward the object side and a positive lens toward the image side, cemented together at a joint surface having a convex surface toward the object side, provided in this order from the magnification side;
• the second lens subgroup satisfying the following conditional formula:
• 3.0<f12/fw<20.0 (1)
• wherein f12 is the focal length of the second lens subgroup, and fw is the focal length of the entire system at the wide angle end.