Pinhole cameras are a fascinating concept and make for a great craft project you can do at home using regular materials. Pinhole cameras work by passing light through a very small aperture into a light-proof box. The light passes through the aperture and projects an upside-down image on the back of the box.
How does a pinhole camera work? (camera obscura)
A pinhole camera works through the camera obscura effect, which is a naturally observed phenomenon. It’s most notably seen during partial solar eclipses, where you can see crescent-shaped shadows on the ground in a thickly shaded area.
Essentially, the light is being blocked by the tree cover, letting very little pass through, and an inverted image is projected on the ground.
This was extrapolated by early scientists to safely look at solar eclipses. As you know, solar eclipses are extremely dangerous to look at with the naked eye. This is because you can’t look at the sun directly with the naked eye anyway!
Just because the sun is partially blocked, the light does not become any less intense, so thinking the light is less and looking directly at an eclipse can do serious damage to the eyes.
Most early uses of the camera obscura effect were done by using a dark room with a curtain. By opening the curtain very slightly, the amount of light let in could be controlled and the image could be observed on the wall opposite the curtain.
This post from Reddit is a great example of a camera obscura in action:
Interestingly enough, camera obscuras have unlimited depth of field, which means everything will always be in focus.
You can either project the image on a translucent screen for viewing, or you can put a film in the box and manually expose it by opening and closing the shutter.
How to make a basic pinhole camera
It’s super easy to make a basic pinhole camera. In fact, it’s so easy and fun to do that an entire business idea was born out of it called the Pop Up Pinhole Company! They started out as a Kickstarter project.
Here’s what you’ll need:
- A cardboard box
- Electrical tape
- A 2 x 2 inch square of aluminum you can cut out of a soda can
What to do:
- First off, take a good look at the box and use electrical tape to seal off any areas where there are small gaps or tears. You need to make sure no light can get in! Keep one side open as you still have to install the shutter.
- Next, choose a point to make your shutter. Ideally, it should be somewhere in the middle of the box.
- Cut out a small (1 x 1 inches is fine) square from the box where your shutter will go.
- Use a pin to prick a hole in the piece of aluminum, and use some sandpaper to smooth the the pinprick down.
- Stick the aluminum square behind the square you cut out: glue will give the strongest bond, but you can certainly use electrical tape to secure it as well.
- Finally, use electrical tape to make a shutter flap on top of the pinhole.
- At this point, you can either cut out the wall directly behind the pinhole and stick some tracing paper on it to see a projection of the image, or you can use some film and open-close the shutter to take photographs.
More pinhole camera tutorials
When to use pinhole cameras
Now that modern cameras are so accessible and in everyone’s pockets, pinhole cameras have become more of something just for fun!
Here are some interesting use cases for pinhole cameras:
- Viewing solar eclipses: solar eclipses are incredibly dangerous to look at directly(the sun is dangerous to look at directly anyway!). Using a camera obscura, you can safely view a solar eclipse. For a solar eclipse, you’ll have to modify the design a bit by using a separate bit of paper for projecting the light. This is because you can’t hold the camera up to the sun and look at the back of the camera at the same time!
- Fun projects with kids on weekends: chances are you’ve got boxes lying around so if the kids are bored, this is a great craft idea to do and kill some time on a dull weekend!
- Teaching people about refraction and cameras: Pinhole cameras do a great job of demonstrating how light and cameras work. What better way to explain the concept than to demonstrate it?
To pinholes and beyond
The laws of light and refraction work in really fascinating ways! The pinhole camera forms the basis for modern photography. It’s amazing how far cameras have come since then.
The very first cameras were adaptations of the pinhole camera, as they were essentially a box where light came in from a tiny aperture on one side and was projected onto a piece of photographic paper on the other side.
Modern cameras are built on the same principles, but they’re a lot more advanced, of course! From mirrorless cameras, SLR cameras, to tiny action cameras, they all rely on light coming through a very small hole(called the aperture) and projecting upside-down on a point behind it.
In the old days, film cameras would capture the light on photographic film which was coated with chemicals that reacted with light.
Digital cameras capture the image on a light-sensitive sensor which immediately processes and saves the image through complex software!