| 摘要 |
PURPOSE:To make rapid focus detection with good responsiveness even for a subject of low luminance and low contrast by simultaneously accumulating charges into photoelectric transducers by using two focus detecting system of a passive system and active system and using the detecting system with which the accumulation ends earlier. CONSTITUTION:An exit pupil 27 of an objective lens 3 is previously divided to two regions 27a, 27b and a field lens 23 is provided behind these regions. Two apertures 20a and 20b are provided to this lens 23 and while the spacing between these apertures is shielded of light by a light shielding part 20c, an IR cut filter 22 is mounted to the apertures 20a and 20b and is covered with a field mask 20 including the light shielding part 20c. A field lens 25 consisting of two lenses 25a, 25b disposed symmetrically with the optical axis is disposed behind the mask and 4 pieces of photodetectors 26a-26d to constitute the photoelectric transducers of a charge accumulation type are provided behind this lens. The active function is provided to the elements 26a, 26b and the passive function is provided to the elements 26c, 26d. The camera shutter is operated by using the output of the elements in which the charges are accumulated earlier in such a manner. |
