Patent ID: 6104550
Filing Date: 2000-08-15
Classification: G02B

Abstract:
A control method for a zoom lens camera comprising:a zoom lens system comprising at least two variable power lens groups, wherein one of said variable power lens groups being provided on the object side functioning as a focusing lens group;a focal length detection mechanism which detects the focal length of said zoom lens system by dividing said focal length into a finite number of steps; anda focus drive mechanism which drives said focusing lens group to selectively move the focusing lens group to a finite number of steps;said method comprising:measuring actual focal points of said zoom lens system at least at the wide angle extremity and the telephoto extremity upon assembly, whereby any deviations of the measured said focal points from a focal plane of said zoom lens camera in an optical axis direction are obtained;converting the deviations in the optical axis direction to a displacement of said focusing lens group at each focal length of said finite number of steps, taking into account the focus sensitivity of said focusing lens group which varies depending on the focal length of said zoom lens system, wherein the data of said displacement is stored in a memory; anddriving said focusing lens group, upon focusing, by said focus drive mechanism in accordance with the displacement of said focusing lens group determined based on object distance data and focal length data, in addition to the stored displacement data.