AUTOMATIC FOCUS DETECTING DEVICE

摘要

PURPOSE:To increase the probability that focus detection is performed by switching algorithm for determining a defocusing quantity for lens driving from defocusing quantities as to plural areas in a photographic picture plane according to the sequence of a camera. CONSTITUTION:A defocusing quantity detecting means 1 calculates the defocusing quantities DFIS1 to DFIS3 as to the plural areas IS1 to IS3 in the photographic picture plane S. A defocusing quantity determining means 2 determines one defocusing quantity DF according to the defocusing quantities DFIS1 to DFIS3 by the defocusing quantity calculating means 1. This defocusing quantity determining means 2 has plural kinds of defocusing quantity determination algorithm, and a selecting means 3 selects defocusing quantity determination algorithm according to the sequence of the camera. Then a focusing decision means 4 makes a focusing decision according to the defocusing quantity DF by using the selected defocusing quantity determination algorithm. Consequently, the probability of the focus detection increases.