Patent ID: 8582212

Claim:
A zoom lens, which comprises, in order from an object side thereof, a first lens group of positive refracting power, a second lens group of negative refracting power, a third lens group of positive refracting power, and a fourth lens group of negative refracting power, wherein: upon zooming from a wide-angle end to a telephoto end of the zoom lens, a separation between the respective lens group changes, a separation between the first lens group and the second lens group becomes wide, and a separation between the second lens group and the third lens group grows narrow; upon focusing from a focusing-on-infinity state to a close-range focusing state, the fourth lens group moves in an optical axis direction; and the following Conditions (1) and (2) are satisfied at the wide-angle end: |(100*( y 1 ′−y 1)/ y 1)|/Δ s< 1.2 (1) |(100*( y 0.7 ′−y 0.7)/ y 0.7)|/Δ s< 1.2 (2) where y1 is the maximum image height on an imaging plane, y0.7 is seven-tenth of the maximum image height, y1′ is a ray height at a position where, when there is a defocus quantity of Δs from time of focusing on infinity as the fourth lens group is moved to an object at infinity, a chief ray having the same angle of view as an image-taking angle of view reaching the image height y1 upon focusing on infinity intersects the imaging plane, y0.7′ is a ray height at a position where, when there is a defocus quantity of Δs from time of focusing on infinity as the fourth lens group is moved to an object at infinity, a chief ray having the same angle of view as an image-taking angle of view reaching the image height y0.7 upon focusing on infinity intersects the imaging plane, and Δs is 8*the maximum image height y1/1000, provided that y1, y0.7, y1′, y0.7′ and Δs are all given in mm.