Patent ID: 8616790

Claim:
An image pickup apparatus to which an interchangeable lens is attachable, the apparatus comprising: first and second terminals for communication with the interchangeable lens; and a control unit configured to judge, when the communication is made with the attached interchangeable lens, in a first communication mode in which a clock signal is output via the first terminal and communication is performed based on the clock signal, whether or not the attached interchangeable lens is available for a second communication mode in which communication is performed without outputting the clock signal via the first terminal, wherein the control unit continues the first communication mode when the control unit judges that the interchangeable lens is unavailable for the second communication mode, wherein the control unit transmits a predetermined signal for baud rate adjustment of the second communication mode via the second terminal, and determines a baud rate of the second communication mode when the control unit judges that the interchangeable lens is available for the second communication mode.