| 摘要 |
Photographic exposure control apparatus for use in a camera incorporating an artificial light source is disclosed. Scene light is monitored through sets of secondary apertures in the main blade assembly of the camera, and the secondary apertures are so arranged with appropriate filters that a detector is provided with visible scene light for a first portion of the exposure period, a predetermined mixture of visible and infrared scene light for a second portion (70) of the exposure interval during which the artificial light is fired (strobe pulse), and exclusively visible scene light for a third and final portion of the exposure interval. Under conditions of medium or high ambient light, the detector meters exclusively visible light. If the artificial light is fired, the detector monitors principally the infrared light reflected from the subject, utilising the phenomenon that infrared light is more uniformly reflected from subjects than is visible light. A predetermined portion of visible light is monitored simultaneously over the second portion (70) of the exposure period during which the artificial light is fired, in order to avoid under-exposure of subjects in low ambient light which emit infrared light strongly, for example green plants. |
