Patent ID: 9709782
Date: 2017-07-18
CPC Classifications: G02B,H04N

Claim:
1. An image-capturing optical system comprising: a positive first lens group; and a positive second lens group, wherein the positive first lens group and the positive second lens group are arranged in order from an object side in the image-capturing optical system, the image-capturing optical system focuses on a close object by moving the second lens group as a whole along a light axis toward the object side, a lens closest to the object side in the second lens group has a convex surface facing the object side, a lens closest to an image side in the second lens group is a positive meniscus lens having a convex surface facing the image side, the image-capturing optical system satisfies following condition expressions (1) to (3) the FL indicates a focal length of the image-capturing optical system, the 1Gr_Fl indicates a focal length of the first lens group, the 2Gr_Fl indicates a focal length of the second lens group, the 1Gr_R_nop indicates a distance from a surface closest to the object side to a position of a back principal point in the first lens group, and the 1Gr_Thi indicates a whole length of the first lens group.