Title:
AUTOMATIC FOCUSING DEVICE
Document Type and Number:
Japanese Patent JPH04294309
Kind Code:
A
Abstract:
PURPOSE:To prevent a focus lens from starting to move in the wrong direction in the beginning of 2nd or succeeding focusing operation in a continuous photographing time. CONSTITUTION:The automatic focusing device is provided newly with a variation detecting circuit for detecting the state of variation in focus evaluated value in a period after the rotation of a focusing motor 8 is stopped temporarily in the continuous image pickup time. The variation detecting circuit 77 calculates the value of a parameter showing the correlation between the focus evaluated value and time in this period according to plural focus evaluated values obtained in the period from the temporary stop of the focusing motor 8 to the start of next movement in the continuous time. Then a control circuit 76 determines the initial rotating direction when the focus motor 8 begins to rotate again according to the parameter value.
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Inventors:
NAKAMURA TAKAHIRO
Application Number:
JP5917291A
Publication Date:
October 19, 1992
Filing Date:
March 22, 1991
Export Citation:
Assignee:
SHARP KK
International Classes:
G02B7/28; G03B13/36; (IPC1-7): G02B7/28; G03B13/36
Domestic Patent References:
| JPS63177105A | 1988-07-21 |
Attorney, Agent or Firm:
Fukami Hisaro (3 outside)