Zoom lens, optical apparatus equipped with the zoom lens and method for forming an image of an object and varying a focal length

摘要

A zoom lens comprises the following lens groups in the order from an object side: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; and a fourth lens group having a positive refracting power; wherein, upon zooming, at least the first lens group and the fourth lens group move to the object side; and wherein, upon focusing, the fourth lens group comprises a front lens group, and a rear lens group arranged with an air space on an image side of the front lens group, and the rear lens group is moved in a direction of an optical axis of the zoom lens.