Hi, The pinhole size is not the problem. The thickness of the material is. At 70mm or less 0.001 inch thickness and thinner is required to allow for side angle view with minimum roll off. A pinhole with the minimal thickness the expected at 120 degree [+/-60] view angle 1 stop roll off at edge. Lenox Laser has laser pinholes for photography in 0.0005 stainless steel. When designing the PinPLUS Pinhole cameras this became an important requirement for the wide angle cameras design. Lenox Laser drilled pinhole of 250 microns [0.010 inches] in 0.0005 stainless steel meet the requirements for 100 degree diagonally view angle of the PinPLUS 64mm.
Paul Prober
