ZOOM-LENS SYSTEM, INTERCHANGEABLE LENS DEVICE, AND CAMERA SYSTEM

摘要

A zoom-lens system wherein a lens group disposed furthest towards the object side and a lens group disposed furthest towards the image side remain fixed with respect to the image plane when zooming and at least three of the lens groups are moving lens groups that move along the optical axis when zooming. This zoom-lens system satisfies the relations M-N = 3 and 0.1 = T1/fW = 1.5, where M represents the total number of lens elements in the moving lens groups, N represents the number of moving lens groups, T1 represents the distance along the optical axis from the lens surface furthest towards the object side in the lens group disposed furthest towards the object side to the lens surface furthest towards the image side in said lens group, and fW represents the d-line focal length of the entire system at the wide-angle end.