| 摘要 |
PURPOSE:To obtain the focus detecting device which performs stable and suitable focus detection without reference to photographic magnification by switching methods for calculating the quantity of defocusing of a focus detection area from the quantities of defocusing of respective blocks according to the photographic magnification. CONSTITUTION:A defocusing quantity determining means 4 determines the quantity of defocusing of a photographic lens from the displacement detection signal outputted by a focus detecting means 3. Further, the calculated photographic magnification is compared with a specific magnification value and when the photographic magnification exceeds a specific magnification value, the quantities of defocusing of the respective blocks are averaged to calculate the quantity of defocusing of a focus detection area from the averaged value. When the photographic magnification is smaller than the specific magnification value, the quantity of defocusing of one block among the quantities of defocusing of the respective block is calculated and the quantity of defocusing of the focus detection area is calculated from the quantity of defocusing. Consequently, the suitable focus detection is stably performed for a main object in a photographic image plane. |
