| 摘要 |
PURPOSE:To take a photograph without any special operation even if a subject comes closer than the limit of short-range photography by providing a device which detects the subject going beyond the limit of short-distance photography, inserts correcting lenses into a photographic lens, and measures the range again. CONSTITUTION:The subject is irradiated with light from an infrared-ray emitting diode 2 through a projection lens 1 and its reflected light is received by a photodetection lens 3, so that a position detection sensor 4 measures the range. Then, the subject is confirmed in a viewfinder 6 and photographed through the photographic lens 10. When the subject is within the limit of short- distance photography, a sliding frame 20 for compensating lenses 17, 18, and 19 attracted and locked by a magnet Mg 1. When the sensor 4 detects the subject going beyond the limit of short-range photography, the sliding frame 20 is unlocked from the magnet Mg 1 to move. The photographic lens 10 is compensated by the compensating lens 17, a viewfinder lens 6 is compensated by the lens 18, and the photodetection lens 3 is compensated by the lens 19. Thus, the compensating lenses are inserted to attain short-range focusing, so short-range photography becomes possible automatically.
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