Anatomy of a pinhole camera

The camera obscura discovery that led to the invention of the pinhole camera can be traced as far back as 5th-century China. It is the simplest form of camera; at its most basic it consists of a light-proof box with tiny hole in one side. The hole acts as the camera's lens, allowing light to enter the box and project an inverted image on the back wall.

 Illustration:  Aidan Meighan

Illustration: Aidan Meighan

LENS This is the pinhole, which enables a cone of light to pass into the box. The diameter of the pinhole has a direct bearing on the sharpness of the image. The smaller the hole, the sharper the image.

CAMERA BOX A dark housing in which the light rays can be trapped, and seen, most clearly. You can use any receptacle, from cardboard boxes to tin cans for this purpose.

LIGHT RAYS Rays of light travel in straight lines and pass through the pinhole. These rays are inverted upon entering the camera and project an image, if the box is dark enough.

MIRROR AND SCREEN As the light rays hit the mirror they are inverted again, so they are viewed the correct way up on the screen. 

Words by contributing editor Duncan Haskell.