ND Throttle Cine Adapter - Canon FD Lens to Nikon Z w/ Vari ND Filter – Fotodiox, Inc. USA
Amazon.com : Vizelex Polar Throttle Lens Mount Adapter - Canon FD & FL 35mm SLR Lens to Micro Four Thirds (MFT, M4/3) Mount Mirrorless Camera Body with Built-in Circular Polarizing Filter :