Patent ID: 8681436

Claim:
An imaging lens comprising: an optical system including in order from an object side to an image side a first lens group having a positive refractive power and a second lens having a positive refractive power to image an optical image of an object, the first lens group and the second lens group being displaced in an extending amount different from one another to be focused on an object of a finite distance, the first lens group including a negative meniscus lens having a convex surface on the object side, a lens having a weak refractive power, and a lens having a positive refractive power, and the second lens group including four lenses or less or five lenses or less having at least one pair of a cemented lens, wherein a focal length f2 of a second lens from the object side in the first lens group, a focal length F of an entire lens system at infinity, an entire length L of the entire lens system at infinity and a maximum image height Y′ satisfy the following conditional expressions 5.0 <|f 2/ F| [1] 3.5 <L/Y′< 4.5 [2].