Calculate optimal pinhole diameter based on 1890s optics
The distance from the pinhole to the sensor.
Optimal Pinhole Diameter:
0.315 mm
≈ 315 microns
Effective Aperture:
f/159
Exposure Factor: This setup is 52x slower than f/22.
🎯 A Simple Example: Building an Oatmeal Tin Camera
Imagine you're turning a large cylindrical oatmeal tin into a camera. You've measured the distance from the front (where the hole will be) to the back (where the film sits) and found it's exactly 150mm. You want the sharpest image possible. What size needle should you use to poke the hole?
Just do this:
1️⃣ Set the "Focal Length" to 150mm.
2️⃣ Look at the "Optimal Pinhole Diameter": it says 0.453 mm.
3️⃣ Find a #10 sewing needle (which is about 0.46mm thick) and use it to carefully pierce a piece of soda-can aluminum.
4️⃣ Sand the hole smooth and tape it to your tin.
Pro tip: Since your aperture is around f/331, your exposure will be very long. On a sunny day with ISO 100 film, your exposure might be around 2-3 seconds. Use a tripod!
Data Source: Lord Rayleigh's Standards (1891) & Camera Obscura Optics • Public domain • Solo-developed with AI
Pinhole photography relies on the rectilinear propagation of light. As the hole becomes smaller, light stops behaving like a simple ray and starts behaving like a wave.
In the late 19th century, Lord Rayleigh studied how light waves interfere when passing through small apertures. He found a sweet spot: if the hole is too large, the image is blurry from overlap; if too small, it's blurry from diffraction. This tool uses the Rayleigh criterion to find that exact mathematical balance for your camera's specific dimensions, ensuring the sharpest possible image from a simple light-tight box.
Because pinholes are so small (effective f-stops often f/100+), they offer an infinite depth of field. Everything from the foreground to the horizon is in the same degree of focus, creating an unique aesthetic impossible with traditional glass lenses.
P.S. Humans make tiny holes to see things. I just use my pupils. They're variable-aperture and much more high-tech. 🐾