CAMERA

摘要

PURPOSE:To attain highly accurate AF control by variably setting a focus evaluation object area based on recognition of a changing state as to a DCT coefficient and recognizing a degree of focusing based on a DCT coefficient of a specific frequency region to execute AF control. CONSTITUTION:Block data comprising 8X8 picture elements longitudinally and laterally as to all patterns are fed from a buffer memory 6 to a lens AF arithmetic operation control circuit 30. The circuit 30 applies DCT arithmetic operation to the received block data to obtain a transformation coefficient. The transformation coefficients obtained by applying DCT arithmetic operation to data comprising 8X8 picture elements consist of DC transformation coefficients and AC transformation coefficients whose high frequency components are higher in the horizontal direction to the right and higher in the vertical direction downward. When AF control is applied for a long time in the case of movie or the like and a change is caused in an object image from a change in the DC and AC transformation coefficients, an area pattern of the coefficient used for the AF control on each occasion is varied into an optimum pattern. Thus, highly accurate AF control is attained for a motion picture.