Photographic lens, camera body, and camera system

A photographic lens which is mountable on a camera body having an electric power supply, comprising:

• a first actuator which selectively receives electric power from the electric power supply;
• a memory which stores first data relating to power supply characteristics for driving said first actuator;
• and
• a receiving unit which receives second data relating to power supply characteristics of the electric power supply,
• wherein the second data is a calculated equivalent output load resistance of the electric power supply through comparison of non-load power supply voltage to load power supply voltage, and electric power is transmitted from the camera body to said first actuator based upon a comparison of the first and second data.

A camera body having an internal electric power supply and mounted to a photographic lens, comprising:

• a power supply characteristics measurement unit which measures and acquires first data relating to power supply characteristics of the electric power supply by comparing non-load power supply voltage to load power supply voltage;
• a transmission unit which selectively transmits the first data from the power supply characteristics measurement unit to the mounted photographic lens;
• and
• a receiving unit which receives decision results indicating actuator power requirements from the mounted photographic lens,
• wherein electric power is transmitted from the camera body to the mounted photographic lens based upon a comparison of the first data and the decision results.

A camera system including a photographic lens mounted on a camera body, comprising:

• an electric power supply disposed within the camera body;
• an actuator disposed within the photographic lens which receives electric power from the electric power supply;
• a memory disposed within the photographic lens which stores first data relating to power supply characteristics for driving said actuator;
• a transmission unit disposed within the photographic lens which transmits the first data from said memory to the camera body;
• a power supply data accumulation unit disposed within the camera body which receives the first data from the transmission unit;
• a power supply characteristics measurement unit disposed within the camera body which measures and acquires second data relating to power supply characteristics of the electric power supply by comparing non-load power supply voltage to load power supply voltage;
• and
• a determination unit disposed within the camera body which determines whether to supply electric power from the electric power supply to said actuator in response to a received actuator drive demand, the first data and the second data.