A camera is provided with an SPD and a PSD suitable for implementing a camera capable of enhancing an accuracy of focusing and/or reducing a cost with a small scale of circuit. In the event that a photography is performed at a relatively short distance, a switch is switched by an MPU to offer a low impedance state. An AF-dedicated photo detector circuit determines a distance I1 and I2 obtained through a pair of signal electrodes of the PSD. On the other hand, in case of a relatively long distance, the MPU switches the switch to offer a high impedance state in accordance with distance data representative of the determined distance, so that an AF-dedicated photo detector circuit determines a distance up to the camera subject in accordance with photo-current I3 obtained from one of the signal electrodes of the PSD. In this manner, in the event that a photography is performed at a relatively long distance, there is performed a processing of determining a distance up to the subject in accordance with a total quantity of light.