Inner and Rear Focusing Systems - RF Lens World - Canon Singapore

Inner and Rear Focusing Systems

AF lenses use actuator motors to move the lens elements into proper position. Therefore, the weight of each lens element greatly affects the focusing speed. Canon has developed technologies for inner focus and rear focus designs that reduce weight by making only some of the lens components (those affecting focus) movable. This change facilitates precise and high-speed autofocus control. The design also makes it easier to downsize the entire optical system, contributing to a smaller overall chassis and improved weight balance for easy holding. Since the entire lens is an integrated unit, this also makes it more robust and durable. While most people tend to focus on the AF performance of the camera (body) itself, in reality the AF performance of the RF lens is an essential factor in determining the AF performance of the entire system.