Zoom lens and imaging apparatus

A zoom lens, comprising, in order from an object side,

• a first lens group having positive refractive power,
• a second lens group having negative refractive power,
• a composite positive lens group having positive refractive power as a whole, and
• a composite negative lens group having negative refractive power as a whole, wherein
• the composite positive lens group comprises, at a most object side, a third lens group having positive refractive power, and comprises one or more lens groups having positive refractive power,
• the composite negative lens group comprises a negative A lens group having negative refractive power and being arranged at a most object side, and comprises a negative B lens group having negative refractive power,
• changing focal length is performed by varying distances between the lens groups, and
• the following conditional expressions are satisfied:
• 3.44<βrt<4.50 (1)
• 0.10<f3/(fw×ft)1/2<0.46 (2)
• where
• βrt:
• composite lateral magnification of the composite negative lens group at a telephoto end,
• f3:
• focal length of the third lens group,
• fw:
• focal length of the zoom lens at a wide angle end, and
• ft:
• focal length of the zoom lens at the telephoto end.