Pinhole Camera / Phone Camera

May 1, 2021

Since the 1600s, people have experimented with light-proof rooms, chambers, or boxes with a small hole in one side, known as a Camera Obscura. With the advent of photographic film or paper, this idea evolved into the Pinhole Camera -- a light-proof box with a tiny hole on one end, and a photo-sensitive material at the other. The hole is uncovered for a period of time, and the light from outside is focused by the tiny hole on the material on the other end of the box. The hole is then covered, and the photo-sensitive material is then processed, revealing an image. If you are a student of photography, chances are you have had a chance to work with a pinhole camera.

In this digital age, where our phones are better cameras than anyone had until recent decades and can hold tens of thousands of images, the idea of a pinhole camera is kind of silly. But it does have an interesting aesthetic, and can be a tool to learn about light.

I had an idea to build a pinhole camera with a cardboard box, but instead of using photo-sensitive material inside that requires chemical processing, I could just use my phone to take a picture of the image projected inside the box. Modern phones have amazing low light abilities, so it's just crazy enough to work. And it does!


What you need:

  • A box
  • Some tape
  • A piece of white paper
  • Your phone. A new-ish phone that has a night mode will work better than one without it.

How to make it:

  1. Start by finding a box of pretty much any size. Something the size of a shoebox is a good place to start.
  2. Use the tape to cover any seams or corners in the box, because we want to keep as much light out as possible.
  3. Tape the white paper to the inside of the box on one end.
  4. On the opposite end of the box, make two holes. One should be large enough for your phone camera lens to see through. With my phone, it has three lenses on the back so I just cut a large enough square hole for all three lenses to fit in, and for the back of the phone to fit flush against the box.
  5. Cover the other hole with tape or aluminum foil, and use a pin to make a small hole.
  6. Close the box and seal it well with tape to prevent any light from entering

The Big Idea

Light enters the box through the tiny hole, and projects an image on the white paper on the opposite side. The phone, on the same side of the box as the tiny hole, can take a photo of the image projected onto the white paper.

Overall schematic: Schematic

Detail of holes to cut: Detail


  • The tiny hole lets in only a tiny amount of light, so your best bet is to do this outside on a sunny day.
  • If you use it inside, then bringing a bright light next to your subject will probably give the best chance at a usable result.
  • Try with different diameters of holes.
  • Use Night Mode on your camera app.
  • Tape the phone to the side of the box, and put tape around the edges to prevent light from seeping in through the phone hole.

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