About this item Smooth surface for effortless mount,infinity focus allowed.The adapters are precision made to insure the perfect fit. Canon STM series lenses don't work with our EOS adapters. Made of brass and aluminum (not plastic), anodized aluminum construction. Compatible Cameras (Including, but not limited to): Olympus PEN E-PL1, E-PL1s, E-PL2, E-PL3, E-P2, E-P3, E-M, OM-D, E-M5, E-M10, compatible with Panasonic Lumix DMC-G1, G2, G3, G10, GX1, GH1, GH2, GF1, GF2, GF3, GF5, GH4, compatible with Panasonic AG-AF100 Mirrorless Digital Cameras, Black Magic Pocket Cinema Camera (BMPCC). As Canon's EOS lenses are electronically control，most Canon EF mount lenses do not feature a manual aperture ring，so when used on our EOS-M4/3, which is a full manual operation adapter ring, the aperture could not be transfered to the camera, it will stop down to its smallest f/stop by default. Adapting full-frame lens to APS-frame or M4/3 frame camera， it will magnify the focal length by 1.6 on Canon, 1.5 on Nikon and compatible with Sony，2.0 on M4/3 camera