Hardware:

M5*12 Hex socket machine screw/bolt x2
M5*14 Hex socket machine screw/bolt x1
M5 8mm OD, 5mm height heatset insert x3
Optional: M5 Washer x3 (place at bolt head)
 

Print with a strong material which does not deform with pressure (Not PLA unless 90% infill or higher.) the screws will be applying a fair amount of pressure, and would be difficult to adjust on the go.

Use loctite blue on the bolts (or just superglue) so that the bolts dont become loose with folding and unfolding.

Designed for the following 1/4 inch screw: 

Mounting point for camera is intentionally offet towards the back to account for front-heavy camera lenses. May not be stable with very long lenses though.