I have both a Canon EF and Nikon F camera. Will my New Petzval 85 lens work with both?
Unfortunately each Petzval 85 lens is designed with either a Canon or Nikon mount, so your lens will not automatically work with both. It is possible to get an adaptor which makes it possible to shoot with a Nikon lens on a Canon camera body (but not an adaptor from Canon lens to Nikon body, since the flange distance is longer for Nikon than Canon).
We would however strongly advise against using such adaptors with the Petzval lens since each lens is precisely calibrated using a collimator for perfect infinite focusing in our production factory. We cannot accept any responsibility for damage to your camera or lens caused by using such an adaptor.