| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens system having three or more lens groups and a focus adjustment method, which allow the interval between focus adjustment groups to be reduced in consideration of the places and focus adjustment directions of the focus adjustment groups. SOLUTION: In the zoom lens system, a first lens group 11 and a second lens group 12 arranged in order from the object side are focus adjustment groups which have the positions adjusted in the direction of the optical axis in order to adjust a focus position when assembled and adjusted, and these focus adjustment groups satisfy a conditional expression (1). The expression (1) is 0.4<äK1(L)-K1(S)}/äK2(L)-K2(S)}<1.6 wherein K1(L), K1(S), K2(L), and K2(S) are focus sensitivities at the end of a longer focal length of the first lens group 11, at the end of a shorter focal length of the first lens group 11, at the end of a longer focal length of the second lens group 12, and at the end of a shorter focal length of the second lens group 12, respectively. COPYRIGHT: (C)2005,JPO&NCIPI |
