The Control Ring Mount Adapter EF-EOS R allows EF-S and EF lenses to be used on EOS R cameras seamlessly and also adds a Lens Control Ring. Photographers who already have a collection of EF-S or EF optics can invest in the EOS R System confidently, knowing their existing lenses will work as expected. The ring is customisable and easy to find without taking the camera from your eye offering tactile manual control over various settings. Customisable functionality The Lens Control Ring can be programmed via the cameras menu to adjust various settings such as aperture, shutter speed, ISO sensitivity and exposure compensation. Tactile, intuitive handling Its easy to find the Lens Control Ring without taking the camera away from your eye. Gentle clicks give a tactile feedback in thirds or halves of a stop (and can be removed via a special Canon service for filmmakers wanting smoother operation) .