Zoom lens and imaging apparatus

A zoom lens, substantially consisting of:

• a first lens group having positive refractive power;
• a second lens group having negative refractive power;
• a third lens group having positive refractive power;
• a fourth lens group having positive refractive power;
• and
• a fifth lens group having negative refractive power, which are arranged in this order from an object side,
• wherein when varying magnification from a wide angle end to a telephoto end, a distance between the first lens group and the second lens group is consistently increased, a distance between the second lens group and the third lens group is consistently decreased, a distance between the third lens group and the fourth lens group is consistently decreased, and a distance between the fourth lens group and the fifth lens group is changed, while all of the lens groups are moved with respect to an image formation position,
• wherein the following formulas (Ca) and (H) are satisfied:
• −5.00≦1−(β5T)2≦−3.30 (Ca)
• 0.10<fw/f3<0.50 (H), where
• β5T:
• an image formation magnification of the fifth lens group when focusing on infinity at the telephoto end;
• fw:
• a focal length of the entire lens system at the wide angle end;
• and
• f3:
• a focal length of the third lens group.