How do photographic cameras work?

Light rays enter our eyes and pass to our brain, which processes the information received to form a known image. A camera does the same thing that our eyes do, it receives the light rays from the outside and transforms them into an image.

How do photographic cameras work?
This is how photographic cameras work. Photo by Alice Donovan Rouse / Unsplash

For hundreds of years human beings have wanted to perpetuate scenarios in time, an objective that surely seemed impossible at the time; however, efforts, research, and perseverance resulted in the photographic camera.

Now, how is this possible? The first step is to understand how we see objects. We can classify them into two types: those that produce light, such as a lamp or fire, and those that receive light, which reflects a part and absorb another, such as when the Sun illuminates our home or when it illuminates the Moon and provides a spectacular view.

A photographic camera is a dark box with a lens inside called an objective, this projects on a photosensitive sensor the light rays of the object we want to capture, whether it generates or reflects them. The lens must be a converging lens due to the physical behavior of light because the object is perceived but upside down! Light is emitted in all directions and the lens is in charge of grouping all these particles in a single point, depending on the distance between the object and the lens, the image will have a larger or smaller size.

The images were stored on a light-sensitive film or roll, and when the button was pressed to take the photograph, the film was uncovered and the light was captured on it, although it was necessary to go to a laboratory to develop the result utilizing special chemical processes.

All very well so far, analog cameras seem to be a history of the past, but what about digital cameras, did you realize that the operation is the same, well yes, with the only difference that now an electronic process saves the image on a memory card.

In a cell phone, the operation is similar, only that the mechanism is much smaller, and technological advances have allowed obtaining higher resolutions, wider scopes, and in general, a quality that at times seems to surpass reality itself.

Curiously, one of the most powerful cameras is the human eye, studies have revealed that this organ captures images with a resolution of up to 576 megapixels compared to high-end phones that only reach 12, of course in this case you save memories rather than images.

By José Francisco Estrada Vázquez, Sources: UASLP