| 摘要 |
PURPOSE:To obtain excellent focuses over a wide range even when the focal length of a lens is varied by making a shift in boundary point for discriminating between a close-distance and a far-distance zone associatively with a change in the focal length of the lens, and changing lens setting positions. CONSTITUTION:A range finding device is equipped with a protection part 23 and a photodetection part 24 which photodetects light reflected by a subject, the output of the photodetection part 24 is processed to decide whether the subject is in the close-distance or far-distance zone, and the lens setting positions are changed by two stages according to the obtained distance zone. A triangular prism 26 is fitted to a prism holder 25 fixed to a lens board 10 and the triangular prism 26 is inserted to before the photodetection part 24 in wide-angle photography and moved away from the photodetection part 24 in telephotography, thus changing boundary points between wide-angle photography and telephotography. |
