| 摘要 |
PURPOSE:To obtain a focus detector for detecting a focus accurately without the influence of temperature change by compensating defocusing variable on the basis of an output of a temperature detecting means. CONSTITUTION:The image of an object obtained from an image-forming optical device 1 is led into a photoelectric converter 2 and the focus of the device 1 is detected on the basis of an output from the converter 2. The titled detector is provided with a defocusing variable calculating means 3 for detecting the difference between the image forming surface of the device 1 and a prescribed detecting surface, i.e. a defocusing variable, from the output of the converter 2, a temperature detecting means 4 for generating an output corresponding to a temperature and a compensating means 5 for compensating the calculated contents or output of the means 3 on the basis of the output of the temperature detecting means. The compensating means 3 calculates the changed value of the defocusing variable due to temperature change from the output of the temperature detecting means 4 and sends the calculated value to the means 3 to compensate its calculated contents or compensates the output of the means 3 by the changed value. |
