| 摘要 |
PURPOSE:To make focusing detection accurate and rapid by evalulating the sharpness of an image by means of the evaluation function values which are optimum respectively when an imaging lens is near the focal position and when it largely defocuses, with the threshold value as a boundary. CONSTITUTION:Light from a subject passes through a taking lens 2 for imaging and part thereof transmits through the translucent mirror part 1a of a movable reflection mirror 1 and is projected to photodetector arrays 8, 9. The respective photodetectors of the photodetector arrays 8, 9 generate the photoelectric conversion signals as analog illuminance signals based on the quantities of the light received therein, respectively. Said signals are converted to digital illuminance signals by a signal processing circuit 14, and are inputted to a central processing unit 15, by which the evaluation function values for fine adjustment and rough adjustment are operated. With the preset threshold value as a boundary, the evaluation function values for rough adjustment and fine adjustment are properly used to enable contrast to be correctly evaluated at all times. In this way, the focusing detection may be accomplished accurately and rapidly. |
