| 摘要 |
PURPOSE:To reduce useless arithmetic operation and to attain focus detection with high responsiveness by changing an arithmetic range in which the 1st and 2nd signals are relatively displaced in accordance with the maximum value of defocusing amount of an image forming optical system to reduce the arithmetic range in accordance with the decrease of the maximum defocusing amount of an image forming optical system. CONSTITUTION:The maximum defocusing amount MD of a lens loaded at present is obtained from a ROM in an intra-lens control circuit LPRS and correlative arithmetic operation is executed in accordance with the information to set up the arithmetic range. Namely, the range of a relative displacement value (k) is increased at the loading of a lens such as a telephoto lens having a large maximum defocusing value, and at the loading of a lens such as a wide angle lens having a small maximum defocusing amount MD, the range of the (k) is reduced. Consequently, the former case can be prevented from the failure of focus detection due to the disappearance of common luminance distribution at the time of large defocusing and the latter case can save the useless arithmetic operating time and shorten the focus detecting time. |
