Patent ID: 9453993
Filing Date: 2016-09-27
CPC Classification: G02B

Claim Text:
1. A variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied; the following conditional expressions being satisfied: where fw denotes a whole system focal length of the variable magnification optical system in the wide-angle end state, f4 denotes a focal length of the fourth lens group, f5 denotes a focal length of the fifth lens group, d4iw denotes a distance on the optical axis from a lens surface on a most image side of the fourth lens group to an image plane in the wide-angle end state, and d4it denotes a distance on the optical axis from the lens surface on the most image side of the fourth lens group to the image plane in the telephoto end state.