Why a special head ? because of Parallax ...

Parallax ? look behind your finger ..

To fix the parallax issue, just rotate the camera around one of its two nodal points.

How to find them ?

The position of the nodal points depends on the lens used, not the camera.

Also, if you have a zoom lens, the position of the nodal points changes as you zoom in and out.

Align the lens and the axe of rotation (Plumb bob or plumb line)

Cancel the parallax by small adjustments

Note your position

Check it by taking two shots

The same detail on opposite sides of the frame