| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic focus detection device capable of realizing accurate and stable focusing operation. SOLUTION: Front and rear optical images conjugate with respect to an optical axis are fetched from an image sensor 8 through an image-forming optical system such as an objective lens 3 for a subject S placed on a stage 1, and a condition is changed in an image-forming optical system. When state detection devices 12 and 13 detect this change, the level of the image signal of the front and the rear optical images outputted from the image sensor 8 is adjusted by a light quantity balance adjusting part 14 based on appropriate gain combination information in accordance with the optical condition at this time. Thereafter, the focusing operation is taken place to the subject S placed on the stage 1 based on the image signal of the adjusted front and rear optical images. |
