This adapter allows C-mount lenses (found in many – but not all – 16mm movie cameras, CCTV cameras, etc) to be mounted on the new Canon EOS-M mirrorless camera range (Canon EOS M, EOS M2, EOS M3, EOS M5, EOS M6, EOS M10)
This adapter is for the new Canon EOS-M mirrorless camera format only and it ***DOES NOT FIT Canon EOS DSLR CAMERAS*** Any C-mount lens attached to a Canon camera cannot be controlled electronically from the camera (i.e. it works in manual focus and manual aperture mode only).
Many C-mount lenses produce an image circle too small to effectively cover the entire Canon camera sensor. This produces what is called ‘vignetting’ (dark circles around the image)