| 摘要 |
A camera which selects a specific image sensor when the photographic lens is scanning, to reduce the focus detection time during scanning. The camera includes first and second image sensors and a photographic lens. Each image sensor receives light passing through the photographic lens, forms a respective image of the subject to be photographed, and produces a sensor output which corresponds to the luminous intensity distribution of the received light. The second image sensor has a higher sensitivity than the first image sensor. A control unit (a) determines whether focus detection is possible; (b) causes the photographic lens to scan when focus detection is not possible; (c) performs focus detection based on the output of the second image sensor when the photographic lens is scanning. Additional embodiments use only one image sensor and amplify the image sensor output during scanning. Moreover, the output of the image sensor could be thinned, or shifted, during scanning to reduce the focus detection calculation time.
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