Allows the use of M42 screw mount lenses on Canon EOS bodies. As the Canon EF mount has a longer flange distance than M42, this adapter maintains infinity focus without the need for a corrective lens element. Fully passive with no electronic contacts, requiring manual aperture control. Works with both full frame and APS-C Canon bodies.

Some lenses may have difficulty with infinity focus on Canon 5D. I'm looking at YOU Industar.