This is a Canon EOS body to Olympus OM Lens Adapter. It allows the use of Olympus lens on Canon EOS mount body. Features: - Works with manual focus and manual exposure metering. - It operates at shooting aperture -- the photographer manually opens or closes the lens aperture using the lens aperture ring. - There is no glass elements in the adapter which would degrade lens performance. - OM lenses with pre-set diaphragms are not usable.