Gimbal head for Tamron 150-600 G2 two-axis

This is my second version:
What has changed:
- Much thinner, but as rigid if not more thanks to PET
- Second axis: also panorama with 2 bearings: a 625 for centering and a rolling plane for transmitting forces. There are still 4x 625 bearing for the tilt axis.
- two way of fixation of the zoom: either sliding with two M3 screw for security (can be equilibrated at any zoom position) or the classical 1/4" screw, equilibrated at 600mm only.
- Level in the center for proper mount on the tripod