Patent ID: 7593631
Filing Date: 2009-09-22
Classification: G02B,G03B

Abstract:
1. A camera having a focusing device comprising: a photographing lens including a focus lens to form an optical image of a subject; a defocus-amount varying direction detecting part which detects the defocus-amount varying direction of the photographing lens; a focus-lens moving mechanism which moves the focus lens; a focus-lens position detecting part which detects the position of the focus lens; a reverse point detection part which detects a reverse point, wherein the reverse point is a position of the focus lens at which a defocus-amount varying direction changes; an autofocus determination part which determines whether the position of the focus lens is located on the far-distance side or the near-distance side of the detected reverse point; and a control part which moves the focus lens (A) using a first defocus amount-to-lens driving amount relationship when the autofocus determination part determines that the position of the focus lens is located on the far-distance side of the detected reverse point and (B) using a second defocus amount-to-lens driving amount relationship when the autofocus determination part determines that the position of the focus lens is located on the near-distance side of the detected reverse point.