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The term camera obscura arises from time to time in the photoraphy arena. I remember the time I first heard the term but knew not what it was. By the second or third time someone mentioned it in passing, I just had to look it up and I'm glad I did. It won't help you take better pictures and you won't earn more money but will gain some knowledge that starts the knowledge drive and understanding of the principles of photography that much further.

If you don't know anything about the camera obscura, you will after this. Did you ever ask yourself why are photographic devices called cameras? They were called cameras because their direct ancestor is the camera obscura, an optical device functioning on the basis of a simple law of physics. Camera Obscura is the Latin for dark room. It is important to understand it is not an invented mechanical device; it works on a naturally occurring phenomenon. It is like a fire or rainbow.

To fully understand the concept, you can try this out: on a bright day, get into a very dark room (you can obtain the darkness by covering the window with an opaque, but thin material). Make a pinhole in the item that covers the window. If the hole is small enough, on the opposite wall you will see the world outside the window, in full color and motion and turned upside down. Your room is now a camera obscura.

Let's see what is the principle of the camera obscura .When the rays reflected from the bright objects outside (this is why you need to make the experiment on a bright day) pass through the pinhole they do not scatter. Instead, they cross and reform as an upside down image on the opposite wall, or on any flat surface held parallel to the hole.

The principles of the camera obscura have been known since antiquity. Its earliest mention was by the Chinese philosopher Mo-Ti in the 5th century BC. His experiment was similar to the one described above. He called the darkened room the 'locked treasure room'. Aristotle (3rd century BC) also understood the principle of the camera obscura. It has been claimed that the Islamic scientist Abu Ali Al-Hasan Ibn al-Haitham (also known as Al-Hazen) is the one who actually discovered it while carrying out some experiments in optics, in the early 11th century, Egypt.

In the 15th century Leonardo da Vinci described camera obscura in Codex Atlanticus. It appears that he was the first who discovered its potential as a drawing aid. In the 17th and 18th century artists such as Johannes Vermeer, Canaletto, Guardi and Paul Sandby were known for their incredible attention to detail. Therefore, it has been speculated that they made use of the camera obscura. If you've seen Girl with a Pearl Earring (a movie about how Vermeer created his masterpiece that gave the name of the film), you must remember that 'magic box' that Griet finds in the artist's atelier and her surprise when he shows her the way it works.

The camera obscura used by artists was not the rudimentary one described in the beginning of the article. The image quality was improved by adding a convex lens into the aperture and a set of mirrors solved the problem of the upside down image.

Let's now understand how din this simple optical device turn into the photographic camera. The camera obscura managed to get an accurate image of the world outside; the only problem remained recording this image. Therefore, adding a sheet of light sensitive material to the little modified camera obscura was enough. This is the way photography was invented in the early 19th century.

Another use of the camera obscura was for entertainment; some camera obscura rooms have been built at the seaside or in areas of scenic beauty as tourist attractions. Some of them still survive. They are large chambers situated in high buildings. A live panorama of the outside is projected inside the room through a rotating lens. Some of you might ask yourselves what is the point of going into a dark room to look at the reflection of something you can see outside. The interesting thing in this kind of experience is not the view itself, but the feeling you get when you are just a spectator of the world that surrounds you.

Personally, I am absolutely fascinated by the camera obscura. There are many interesting things about it that I did not mention in this article. For instance, with its aid, you can experiment that light travels in time, with speed, and even calculate the speed of light. This was Al-Hazen's discovery. Another interesting thing is that the German astronomer Johannes Kepler used a camera obscura for his astronomical observations. And there is much more to find out about this magical device...