Interchangeable lens and camera body communicating whether data transmission was normal or abnormal

An interchangeable lens that can be detachably fitted to a camera body, the interchangeable lens comprising:

• a clock signal reception unit that receives a clock signal outputted from the camera body;
• a control command reception unit that receives a control command and data signal from the camera body, the control command and data signal being in synchrony with the clock signal, specifying a control command for the interchangeable lens and including type data specifying a type of the control command;
• a response generation unit that generates a response data signal including the type data based on the control command and data signal that has been received;
• and
• a response transmission unit that transmits the response data signal to the camera body while the control command reception unit is receiving the control command and data signal from the camera body in a next communication cycle in synchrony with the clock signal received by the clock signal reception unit, wherein
• if the control command and data signal is normally received, the response generation unit generates the response data including the type data based on the type data in the normally received control command and data signal, and if the control command and data signal is not normally received, the response generation unit holds the response data that has been generated based on the normally received control command and data signal in a previous communication cycle.