Title:
AUTOMATIC FOCUSING DEVICE FOR ELECTRONIC CAMERA
Document Type and Number:
Japanese Patent JPH04161912
Kind Code:
A
Abstract:
PURPOSE:To perform quick focusing control by providing a focus lens position detecting means, an evaluation value generating means, an external distance measuring means, an arithmetic means and a control means. CONSTITUTION:A CPU 20 is inputted with an evaluation value fed from an AF detection circuit 18 at the preset cycle and judges whether the focal point is located in front or rear of the present focus lens position based on the distance information fed from a photographing distance arithmetic circuit 24 and the distance information fed from an external distance measurement section 30 when the evaluation value is the preset threshold value or below. The CPU 20 moves a focus lens 10D in the determined shift direction at a high speed via a driving circuit 40 and a focus motor 42. When the evaluation value becomes a fixed level or above, the CPU 20 judges that the focal point is near, switches the speed of the focus motor 42 to a low speed, climb-controls the lens 10D, and stops it at the position where the evaluation value becomes maximum. Quick focusing control can be performed for focusing with an image signal.
Inventors:
KASHIWANUMA YASUNORI
MIKAJIRI SATOSHI
MIKAJIRI SATOSHI
Application Number:
JP28743990A
Publication Date:
June 05, 1992
Filing Date:
October 25, 1990
Export Citation:
Assignee:
FUJI PHOTO OPTICAL CO LTD
FUJI PHOTO FILM CO LTD
FUJI PHOTO FILM CO LTD
International Classes:
G02B7/36; H04N5/232; (IPC1-7): G02B7/36; H04N5/232
Domestic Patent References:
| JPS61235809A | 1986-10-21 | |||
| JPS6269218A | 1987-03-30 |
Attorney, Agent or Firm:
Kenzo Matsuura