Camera Obscura – The Pinhole Camera
The principle of the pinhole camera has been known for more than 2,000 years. Aristotle was among the first to observe and describe it while watching a partial eclipse of the Sun. Sunlight passed through small openings in the tree canopy, creating images of the solar disc on the ground. Aristotle also noticed that the smaller the opening, the sharper the image.
From Painters to the First Camera
Later, this principle began to be used in painting. The pinhole camera, often as large as a small room, served as a tool for tracing scenes. Light entering through a small opening in the wall created an inverted image of the scene outside on the opposite wall. The artist inside the camera obscura would trace the outlines of the projected image in charcoal. However, the inverted image was not ideal for painters, so a mirror was used to turn it the right way up.
Camera obscuras gradually evolved. Portable versions also appeared, some resembling tents that artists could take with them on their travels. Later, an aperture and a simple lens were added. Miniaturising this improved camera obscura eventually led to the invention of the first photographic camera.
My First Experiments
I began experimenting with camera obscura several years ago in a children’s photography club. The children made simple cameras from shoeboxes or small boxes assembled from cardboard. They used a pin to make a tiny hole and attached photographic paper to the back wall. These primitive devices produced our first photographs. The results were far from perfect, but they had a charm of their own — each image was unique and often shaped by chance.
The Importance of Aperture Precision
Today, I use more sophisticated cameras, although the basic principle remains the same. The precision of the pinhole has the greatest influence on image quality. It must be perfectly round, not ragged as it would be if made with a pin. The diameter of the hole in relation to the distance to the light-sensitive material is equally important. The pinholes in the cameras I use measure between 0.15 and 0.3 mm in diameter.
Photographing on Roll Film
Another improvement is the use of roll film. Its main practical advantage is that I do not have to go into a darkroom — a room with absolutely no light — to change the film after every exposure. With ISO 100/21° film, exposure times on a sunny day are approximately 2 to 6 seconds. In weaker light, they can range from several minutes to tens of minutes. I determine the exposure time using a light meter and then use a conversion table to calculate the appropriate exposure. Depending on the pinhole diameter, the aperture is around f/190. Such a high f-number provides one of the greatest advantages of pinhole photography: an enormous, almost infinite depth of field.
The Magic of Camera Obscura
I first encountered the principle of the pinhole camera more than 25 years ago. By chance, in a dark room, we saw an inverted image of a television in the next room projected through a keyhole. The image on the white wall was much larger than the actual screen, and the whole phenomenon seemed almost magical.
Today, I know exactly how this effect occurs, but the magic of camera obscura still fascinates me.
Pinhole Photography in Practice
You can see the pinhole camera principle in practice in my own photographs. Explore my pinhole photography galleries to discover images created with different pinhole cameras.