Canon 2971C002 Overview Extending the range of compatible lenses, the Canon Mount Adapter EF-EOS R is a lightweight, compact lens adapter designed for attaching any EF or EF-S-mount lens to the EOS R mirrorless digital camera. This simple adapter retains full autofocus and image stabilization capabilities and contains no optical components, thereby maintaining the original optical quality of the mounted lens. It is also dust- and water-resistant, making it suitable for use in harsh weather conditions.