| 摘要 |
PROBLEM TO BE SOLVED: To prevent degradation of focus detection precision or impossibility of focus detection even in a high-temperature environment regardless of a dark field. SOLUTION: A focus detector is provided with an image sensor 3 which receives light from a subject, which has passed an objective lens 1, and outputs an image signal corresponding to a luminance distribution of the subject, an amplifier 4 which has a plurality of amplification factors and amplifies the image signal, an arithmetic part 6 which calculates a focusing state of the objective lens 1 on the basis of the image signal amplified by the amplifier 4, and an arithmetic part 6 which sets a charge storage time of the image sensor 3 and an amplification factor of the amplifier 4, which give the most suitable level to the image signal amplified by the amplifier 4. The focus detector is provided with a temperature sensor 10 for detecting an ambient temperature, and the arithmetic part sets a lower amplification factor for a higher ambient temperature detected with the same subject luminance. COPYRIGHT: (C)2004,JPO |
