TTL PHOTOMETRIC DEVICE OF AUTOMATIC EXPOSURE CONTROLLING SINGLEELENS REFLEX CAMERA

摘要

PURPOSE:To make it possible to select mean photometry or spot photometry freely by making at least part of a moving reflex mirror transparent or translucent and by measuring the reflected light and transmitted light of the luminous flux of an object from a photographic lens. CONSTITUTION:Photodetector 11 for mean photometry for display or photodetector 14 for spot photometry for display is connected to the 1st photometric circuit 17 via selection switch S1, and exposure display circuit 18 provides exposure display corresponding to its output. Photometric element 16 for control consists of the 1st photodetection part 16a for the spot photometry and the 2nd photodetection part 16b for the mean photometry connected in parallel to the 1st photodetection part 16a and in switching between those photodetection parts, mean-spot change-over switch S2 interlocking with selection switch S1 selects the output of only the 1st photodetection part 16a or the composite output of the 1st and 2nd photodetection parts 16a and 16b to perform exposure control by exposure controlling circuit 23. This constitution makes it possible to select the mean or spot photometry freely.