Invention Grant
- Patent Title: Focus detection apparatus, method for controlling the same, and image capturing apparatus having a focus detection apparatus
- Patent Title (中): 对焦检测装置及其控制方法以及具有焦点检测装置的摄像装置
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Application No.: US13417766Application Date: 2012-03-12
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Publication No.: US08866955B2Publication Date: 2014-10-21
- Inventor: Masahiro Kawarada
- Applicant: Masahiro Kawarada
- Applicant Address: JP Tokyo
- Assignee: Canon Kabushiki Kaisha
- Current Assignee: Canon Kabushiki Kaisha
- Current Assignee Address: JP Tokyo
- Agency: Cowan, Liebowitz & Latman, P.C.
- Priority: JP2011-066556 20110324
- Main IPC: G03B13/00
- IPC: G03B13/00 ; H04N5/232 ; G02B7/36 ; G03B13/36

Abstract:
A focal position is searched for by contrast evaluation method, the focus lens is stopped once it is detected that the focus lens has passed the focal position, and the defocus amount at the stopping position is found. The defocus amount corresponding to the difference between the focal position and the stopping position is subtracted from this defocus amount to compute a correction value for the defocus amount. Consequently, a correction value for the focus detection result by phase-difference detection method can be obtained accurately in a focus detection apparatus capable of automatic focus detection by phase-difference detection method and contrast evaluation method, as well as a method for controlling this apparatus.
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