I recently came across a very curious cube camera. Without a viewfinder, mode selection, and even without a focus ring. And the size is quite modest: if desired, the Lytro ILLum will even fit into your pocket. The baby’s sensor is able to read vector information about the light at each point. This means that this camera allows you to select or change the focus point after shooting. It is curious that the development of technology has returned to its original point — a camera without a lens.
Initially, a lens was not needed, there was no settings wheel, and even the camera itself, in fact, was not there either. And the picture still came out. It’s about the camera obscura.
What is it all about?
The camera obscura is the simplest optical device for obtaining an imprint of light, and with it everything around that this light will outline. Almost like shooting with a wide-angle lens, only without a lens.
The process of obtaining an image in a camera obscura is based on the physical properties of light. In a completely dark space (for example, a square black box), a small diameter hole is created on one of the planes. As a rule, it does not exceed a couple of millimeters. The light, and with it the entire exposure behind this hole, is projected upside down onto the opposite plane to the hole. The image size directly depends on the distance between the hole and the opposite plane. And its sharpness is directly related to the diameter: the smaller it is, the image is sharper.
The principle of operation is similar to how the human eye works. The image enters the camera, just as the environment around us is read by sight: through a small hole (the pupil) and upside down. The light enters the hole at an angle, the rays reflected from the top of the objects go down, and those that are reflected from the objects near the ground rush up. In the dark space of the camera, the rays intersect and, consequently, the picture is flipped. In our case, the image is turned over by the brain, and in modern cameras this happens due to the mirror.
Photography without lenses
The property of light to project objects was discovered in the Middle Ages. An analysis of the physics of light and the first portable camera obscura can be found in Da Vinci’s drawings. Similar optical devices are described by many European physicists and scientists of that time.
The portable camera obscura, a kind of box with a hole, became widespread by the 17th and 18th centuries. Scientists used it for observations, artists used it as an auxiliary tool, and photographers… photographers started with it! Craftsmen from the 19th century figured out how to catch the image projected onto the wall: all you had to do was attach metal plates coated with a photosensitive composition. And so photography was born.
Back to the present
The camera obscura still exists today. It’s just called Pinhole.
At the moment of its birth, the pinhole was a classic camera obscura, only with a touch of modernity: why big wooden boxes with photographic plates when there is 135mm film? Everything is much more compact and simpler. The most ascetic version of a pinhole is a matchbox camera with a film reel and a take-up reel attached. And the role of optics is performed by a tiny hole made by a needle on adhesive tape.
Such a camera can be made from improvised materials, the main thing is to fix two reels and calculate the correct distance between frames and the distance from the film to the hole. Of course, exposure is also by eye. As a rule, in such cases, one frame is exposed from several minutes to several hours, depending on the level of lighting, film and time of day.
Pinhole is not limited to analog photography: your Canon, Nikon, Sony and just about any camera can also be fitted with a pinhole lens. And there is always the option to arm yourself with a heated needle and make a hole in the plastic plug on the camera body. She will become the lens. In the case of digital cameras, this is much more control over the process, settings and a field for experimentation. It will be possible to look at the result and be surprised at the physics of light right away!