Action-shooting with the massive Rodenstock TV-Heligon 50mm f/0.75 on the tiny Z30 is a lot of fun -- sort of. The lens is glacially slow in its manual focusing as the focusing threads have a fine pitch, thus unless you have pre-focused to the approximate distance one is apt to miss the action.
I continue to be amazed of the optical performance of this 50+ year old design at an effective f/0.75. Since the shutter speed of the Z30 maxes out at 1/4000sec, I now use an ND8X filter on the lens for daylight use. This just barely makes the shutter speeds to fall in the available range