| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system that has focus lens groups with small size and weight and has high optical performance over the entire object distance.SOLUTION: An optical system includes a plurality of lens groups, and the distance between the adjacent lens groups changes in focusing. The optical system includes a lens group L1 having a positive refractive power arranged on the most object side, two focus lens groups L2 and L4 having a negative refractive power moving in focusing, and an intermediate lens group L3 having a positive refractive power between the two focus lens groups. When the focal distances of the two focus lens groups L2 and L4 are fn1 and fn2, and the amount of movement of the two focus lens groups in focusing from the infinite distance to the point-blank range are mn1 and mn2, the conditional expressions: -0.80<mn1/fn1<-0.22, and 0.80<mn2/fn2<-0.22 are satisfied. |
