Patent ID: 8111981

Claim:
A camera to which a photographing lens having a focus lens is attachable, comprising: a focus detection unit which detects a defocus state of the photographing lens from a phase difference between two output signals; a pair of light-receiving units which receives at least a pair of light beams passing through the photographing lens and outputs signals to said focus detection unit, said light-receiving units receiving the light beams in a plurality of segmented areas; a communication unit which acquires information of the attached photographing lens including a maximum defocus amount which can be generated by the attached photographing lens and current position information of the attached photographing lens by means of communicating with the attached photographing lens; and an area determination unit which sets a middle area for detecting the defocus state and peripheral areas for detecting the defocus state in remaining areas adjacent to the middle area based on information of the attached photographing lens including the maximum defocus amount and current position information.