| 摘要 |
PURPOSE:To improve the accuracy of focus detection by using a ring-form lens and specifying the disposition of photoelectric transducers. CONSTITUTION:A ring-form lens 9 whose central part 9a is optically shielded and a photoelectric detection plate 10 disposed with a plurality of photoelectric transducers 10a, 10b groups intermittently and at an equal spacing within the ring form range are disposed within the reflected light path of the photo splitting mirror 8 provided to the inside center of a condenser lens 7. As a result of this, part of the subject light imaging on a finder screen 3a by way of an interchangeable type photographing lens 1 and mirror 3 is split to a plurality of partial oblique luminous fluxes through the photo splitting mirror 8 and ring-form transmission part 9b and these luminous fluxes enter photoelectric transducers 10a, 10b. By subsequently or simultaneously measuring the photoelectric transducer 10a, 10b groups, the output difference between the respective elements or the maximum value and minimum value differences of the element group outputs are detected, whereby the focus detection is accomplished with high accuracy. |
