Zoom lens and imaging apparatus

A zoom lens comprising:

• in order from an object side thereof,
• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a stop;
• a third lens group having a positive refractive power;
• and
• a fourth lens group having a positive refractive power,
• wherein zooming of the zoom lens is performed by moving at least the first lens group, the second lens group, the stop, and the third lens group along an optical axis of the zoom lens,
• when the zooming is performed, the stop is moved so as to be closer to an image plane at a wide-angle end than at a telephoto end of the zoom lens and to be closer to the second lens group at the telephoto end than at the wide-angle end, and
• the following conditional expressions are satisfied:
• 4.0<f1/fw<7.0 (1)
• 0.2<X1/ft<0.3 (2)
• wherein
• fw represents a focal length of the zoom lens at the wide-angle end,
• ft represents a focal length of the zoom lens at the telephoto end,
• f1 represents a composite focal length of the first lens group, and
• x1 represents a displacement of the first lens group during the zooming from the wide-angle end to the telephoto end.