quick question. Flange focal distance. This tells you what should be the distance between the mounting part of the lens and the image. For super angulon 65mm f8 it's 70,5mm. But where is the focus in this case. At infinit? If I want to use a helicoid focusing ring than 70,5mm distance hould be when it's set to infinity? Or where?

Hope someone will understand... thanks!