| 主权项 |
1. An image forming lens system comprising in order from an object side to an image side along an optical axis:
a front lens unit having a positive refractive power; and a rear lens unit, wherein the image forming lens system does not include any other lens unit on the optical axis, and the front lens unit includes in order from the object side to the image side, a first lens unit having a positive refractive power, and a second lens unit having a negative refractive power, and each of the first lens unit and the second lens unit includes a positive lens and a negative lens, and the second lens unit is a focusing lens unit, and the focusing lens unit moves toward an image side along the optical axis at the time of focusing operation from an object at infinity to an object at a close distance, and the rear lens unit includes a positive lens and a negative lens, and the second lens unit is the only lens unit that moves, in the front lens unit, and the following conditional expressions (1) and (2′) are satisfied:
0.5<fFF/f<1.65 (1)0≦|f/rG2b|<6.5 (2′) where, fFF denotes a focal length of the front lens unit at the time of focusing at an object at infinity, f denotes a focal length of the image forming lens system at the time of focusing at an object at infinity, and rG2b denotes a paraxial radius of curvature of a lens surface on the object side of the second lens unit, immediately before the object. |
