Neewer ball head lens mount_Bronica RF645 The B50 side attaches to

The B50 side attaches to the outer bayonet of the lens

and "RF" modes

so it's not a perfect fit

According to the April 1982 Popular Photography

good mechanical function

Neewer ball head lens mount_Bronica RF645 The B50 side attaches toThis Neewer ball head features independent pan and ball locks, a drag control, and a standard Arca compatible clamp for camera mounting (one plate is included). What makes it unusual is the short pan handle, which transforms this into a I guess sort of video head? Certainly makes things a bit easier, if you just want to pan smoothly. Either way, the handle is there, and you can remove it if you really want to. In excellent condition.