An image-pickup apparatus provided with an auto-focus capability. A first unit is configured to input a first trigger signal to initiate a distance measuring operation. A second unit is configured to input a second trigger signal to initiate a photographing operation. A setting unit is configured to set a substrate bias voltage applied to an imaging device included in the image-pickup apparatus. The setting unit is configured to set the substrate bias voltage one of during and after an auto-focus operation when the second trigger signal is input before expiration of a predetermined period of time after inputting the first trigger signal.