The distance from front lens element to the rear lens element (f) is fixed.
The shutter is the part of the lens ,we also can see inside which have no empty spaces.
And thank you to Rod information have wake me up to found the news Rodens information.
the news Rodens 32 HR can be work with the Sory A7
As the Flange focus length (d=69.2) – Flange to lens end (e=46.9)
The space from (Rodens32) Flange lens end to Sony flange at the infinity = 69.2-46.9-18= 4.3 mm