AUTOMATIC FOCUSING DEVICE

摘要

PROBLEM TO BE SOLVED: To perform focusing in a short time even in the case of photographing a low contrast subject such as a white subject in a white background or a black subject in a dark scene. SOLUTION: An electrical signal outputted from a charge coupled element(CCD) 11 is nonlinearly digitally converted by a nonlinear converter 23. By such nonlinear digital conversion, the contrast of an image having uniform luminosity is emphasized. A digital signal on which the contrast is emphasized is supplied to a focus evaluating device 20. The evaluating device 20 accurately detects the maximum value of a high frequency component amount within a focus evaluating range by using the digital signal on which the contrast is emphasized.