Compatible with almost all Canon EOS series (EF/EF-S mount) with manual mode and AV mode. You will be able to get stop down manual exposure,aperture priority exposure. Lens aperture and focusing will have to be controlled manually. It allows the use of Extension Tubes and other accessories to further expand its flexibility. So far,tests show this mount adapter works great with Rollei 85mm F/1.4,50mm F/1.4,35mm F/1.4 and 35mm F/2.8 on both EOS Digital and Film SLRs. It is not compatible with Rollei 50mm F1.8.