Make a pinhole camera

This activity is part of our Science Lab series. Check out the ANU Science Lab for more experiments! In this activity, you will construct a pinhole camera (camera obscura) using a cardboard box to explore optics, light projection, and the history of photography. Watch the video above to see how it's done.

Pinhole camera materials

For this experiment:

• A cardboard box 
• 2 sheets of plain white paper
• Opaque black tape or duct tape (to block all light leaks)
• A push pin or needle
• Scissors or a box cutter
• Clear tape

Safety Note: This project involves using sharp tools like box cutters, scissors, and pins to cut through thick cardboard. Adult supervision is recommended.

How to make a pinhole camera: Step-by-step instructions

Step 1: Prepare the internal screen

1. Cut a sheet of plain white paper to fit flat against the inside bottom surface of your cardboard box.
2. Secure the paper in place using tape or glue. This smooth white surface acts as your viewing screen where the projected image will appear.

Step 2: Seal and shape the box

1. Fold the flaps of your cardboard box closed. Leave a slight gap or adjust the depth so there is plenty of internal space for light rays to travel across.
2. Carefully cut out a small rectangular section on the box where your pinhole and viewing window will sit. Watch the video above to understand the best place to cut.
3. Wrap opaque tape or duct tape over all seams, corners, and joints of the box to completely block out external light leakage.

Step 3: Create the viewing window and pinhole

1. Cut a small rectangular viewing window (viewfinder) on the taped end of the box so you can comfortably look inside with one eye.
2. Next to the viewing window, cover a small opening with tape and use a sharp pin or needle to poke a single, clean pinhole through it.
3. Peer into your viewing window while covering the pinhole with your finger to ensure the interior of the box is completely dark.

Step 4: Test your camera obscura

1. Take your pinhole camera outside on a bright, sunny day.
2. Turn your back to a bright object (like a building, tree, or clear blue sky) and look into the viewing window while pointing the pinhole toward the brightly lit scene.
3. Observe the projected image formed on the white paper screen at the back of the box.

How does a pinhole camera work? The science explained

A pinhole camera operates on the physical principles of optics and light rays travelling in straight lines, a phenomenon known as a camera obscura (Latin for "dark room").

Light reflects off objects in all directions. When you point your camera toward a scene:

• Light rays from the top of an object travel in a straight line through the tiny pinhole and strike the bottom of the white paper screen inside.
• Light rays from the bottom of the object travel straight through the pinhole and land near the top of the screen.
• Because the light rays cross over as they pass through the narrow pinhole, the image projected onto the screen appears completely inverted (upside down) and reversed left-to-right.

Science fair projects & taking it further: Experimenting with variables

Once you have built your basic camera obscura, try tweaking your setup to see how different adjustments affect image clarity and brightness:

• Pinhole size: What happens if you make the pinhole slightly larger using a larger needle, or smaller using a tiny pin? A larger hole lets in more light (making the image brighter), but causes the image to look blurrier because light rays overlap.
• Box length: What happens if you use a much longer or shorter box? Changing the distance between the pinhole and the screen alters the size and focus of the projected image.
• Aperture shape: Try making a square or triangular pinhole. Does the shape of the hole change the shape of the projected image?

Enjoyed this experiment? Explore more hands-on activities on the Science Lab ANU YouTube channel.