Patent ID: 9019618
Filing Date: 2015-04-28
Classification: G02B

Abstract:
1. A variable focal length lens system, comprising: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a negative refracting power; a fourth lens group having a positive refracting power; and a fifth lens group having a positive refracting power; the first, second, third, fourth and fifth lens groups being disposed in order from the object side to the image side; all of the first to fifth lens groups moving, when a positional state of the variable focal length lens system changes from a wide angle end state to a telephoto end state, such that an air gap between the first and second lens groups increases, an air gap between the second and third lens groups changes, an air gap between the third and fourth lens groups decreases, and an air gap between the fourth and fifth lens groups decreases; the fifth lens group being configured from a first sub lens group having a positive refracting power and a second sub lens group disposed on the image side with respect to the first sub lens group with an air gap left therebetween and having a negative refracting power; and the variable focal length lens system satisfying the following expression (1): where Dsub is the air gap between the first and second sub lens groups on an optical axis, and fw is a focal length of the entire lens system in the wide angle end state, wherein the variable focal length lens system further satisfies the following expression (2): where f