76.5mm clamp to M65x1 male thread adapter Canon EOS (EF) Its lenses will vignette on

Its lenses will vignette on many MFT cameras

Just a mechanical coupling

so all your mounted objectives will have same 45mm parfocal height

But it seems like Sigma has bit different mount tolerances

Rear side - Pentax 645 mount

76.5mm clamp to M65x1 male thread adapter Canon EOS (EF) Its lenses will vignette on<ul> <li>Front side 76. 5mm inner diameter< li> <li>Rear side M65x1 male thread< li> < ul> <p>This adapter allows using lenses with 76. 5mm rear diameter of focusing helicoids with M65x1 thread.< p> <p>Made of high quality aluminium alloy.< p> <p>A lens is secured by three screws. Flat steel tension spring protects a lens body from damage.< p> <p><b>Known compatible lenses:< b>< p> <ul> <li>Dallmeyer Pentac 8 inch F2. 9 lens< li> < ul>