Tool walkthrough · 0:49 · silent, with on-screen words
A walkthrough of the Pinhole Optics Calculator, recorded from the real tool: choose a can and paper, read the f-number and the best hole size, then try a Guyana Milo tin.
A silent walkthrough recorded from the real Pinhole Optics Calculator on this site, with the cursor and on-screen words showing each step.
With the default Monster (16 oz / 473 ml) can, Ilford Multigrade RC 5×7" and a 0.48 mm hole the calculator reads a focal length of 85.0 mm, f/177, an optimal 2R pinhole of 0.361 mm, a Sun disk of 0.61 mm and a capture of ±77° by ±44°. With the optimal hole it works at f/235. A Milo tin (500 g — Guyana / Caribbean) gives an optimal hole of 0.487 mm and a capture of ±43° by ±28°.
0:00 The Pinhole Optics Calculator works out the camera a can makes: its f-number, its best hole and how much sky it sees.
0:04 Start with the container and the paper. The defaults are a Monster (16 oz / 473 ml) can and Ilford Multigrade RC 5×7".
0:11 Choosing a container fills in the focal length: 85.0 mm from the pinhole to the middle of the can's base.
0:16 With the default 0.48 mm hole the camera works at f/177. Rayleigh's best hole for this can is 0.361 mm.
0:25 Use optimal diameter copies 0.361 mm into the hole size, and the f-number becomes f/235.
0:32 The paper sees ±77° left and right and ±44° up and down; the Sun draws a trail 0.61 mm wide.
0:37 A Milo tin (500 g — Guyana / Caribbean) is wider: its best hole is 0.487 mm, and it sees ±43° by ±28°.
0:45 Measure your own can, set the hole you can make, then open the full simulator to see the Sun’s trails.