The formula is: d=c√fxl d= pinhole diameter - c= constant = 1.9 - f= focal distance - l= wavelength of the light The wavelength that is mostly used is the one of yellow light = 0.000550 (For use with infrared film for instance, one could use another value).

How do you calculate pinhole camera?

The f-number of the camera may be calculated by dividing the distance from the pinhole to the imaging plane (the focal length) by the diameter of the pinhole. For example, a camera with a 0.5 mm diameter pinhole, and a 50 mm focal length would have an f-number of 50/0.5, or 100 (f/100 in conventional notation).

How do you measure pinhole size?

Using a millimeter distance on the ruler, visually divide the width of the pinhole into fractions of the distance between the marks. It is relatively easy to think of the hole as being approximately 1/4, 1/3rd or 1/2 the distance of the marks. Each 1/4 of a millimeter is equal to . 25 mm.