IMAGE FORMATION LENS SYSTEM AND IMAGING DEVICE INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an image formation lens system and an imaging device including the same that are excellent in maneuverability and have aberrations excellently corrected.SOLUTION: An image formation lens system includes, in order from an object side to an image side along an optical axis,: a front side lens group that has positive refractive power; and a rear side lens group, but does not include other lens groups on an optical axis. The front side lens group includes, in order from the object side to the image side, a first lens group that has the positive refractive power, and a second lens group that has negative refractive power, and each of the first lens group and the second lens group has a positive lens and a negative lens. The second lens group is a focusing lens group, and the focusing lens group is configured to move to the image side along the optical axis upon a focusing action from an object at infinity to the object at the closest distance, and the rear side lens group has a positive lens and a negative lens. A moving lens group in the front side lens group is only the second lens group, and the image formation lens system satisfies following conditional expressions (1) 0.5