| 摘要 |
A camera having a pointing aid emitter that is operable by the user to produce a output beam generally aligned with the optical axis of the camera objective lens such that the output beam illuminates an object in the scene includes a timer for inhibiting repetitious operation of the emitter to reduce the risk of damage to the object that is illuminated by the beam. In a preferred embodiment of a still camera, the operation of the emitter is initiated by partial depression of the camera image capture button so that the beam is emitted and terminated prior to camera shutter opening. The scene captured on full depression of the image capture button is not illuminated by the beam. After light emission and is halted by release of the image capture button or time out of a maximum emission time interval, further attempts to repeat the operation of the emitter are inhibited for a set time period. In a further embodiment, a running time and maximum cumulative emission time interval are employed to allow repetitious emission of the output beam as long as the cumulative repetition time in the running time interval does not exceed the maximum cumulative time interval. The camera preferably includes an ambient light measuring system and a distance measuring system for providing automatic modulation of the power of the light beam emitted during each emission and inhibition of the emission at excessive or insufficient camera-to-object distances. The emitter preferably comprises a laser light source that produces a visible laser output beam.
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