AUTOMATIC FOCUS CONTROL DEVICE AND AUTOMATIC FOCUS DETECTING DEVICE

摘要

PURPOSE:To make focusing not be affected by the change-over of the F value mode by calculating the quantity of defocusing from the output signal of 2 pairs of photoelectric element groups detected by dividing a subject image, correcting the defocusing signal according to the change- over of the F value mode and making the relation between the quantity of defocusing and the leading-out distance of a photographic lens constant. CONSTITUTION:In order to find phase difference j' of a subject image from outputs a1-an and b1-bn of CCD25 consisting of 2 pairs of photoelectric element groups A1-An and B1-Bn, ai and aj are stored in memories 33 and 32 and signals shifted by j, bi-j and bi+1-j, are stored in memories 36 and 35 respectively through AD converter 39, memories 30 and 31 and shifting circuit 34. Peak value Y1 of integration value of (ai-bij)q can be obtained from the output of memories 33 and 36 through differential circuit 37 and cumulative circuit 39. The output of zero-cross detecting circuit 47 for the similar operational output of the integration value of the difference between (ai-bi+1-j)p and (ai+1-bi-j)p and phse difference j' from Y1 are sent from operational circuit 48 to control circuit 26, the variation of j' caused by F value switching is denied through F value mode circuit 50 and a fixed defocusing signal is outputted from circuit 26.