About Camera Prisms
Do you ever wonder what makes a camera work? It seems simple enough to look through the lens, point and click, but very few of us ever take the time to figure out what enables the camera to take a photograph.
Without camera prisms, taking pictures would be virtually impossible. They are the reason that cameras function the way they do.
The prism is a part of what makes the SLR camera, or the single lens reflex camera, work. An automatic mirror system that is capable of moving is used in the SLR camera. This component allows the person taking the photograph to see what she will be capturing on film.
History
The obscura camera was the first camera, developed somewhere between 390 and 470 B.C. Though the obscura may sound like a fancy type of camera, it was actually just a completely dark room. These "cameras" could be as big as a house or as tiny as a box. The inside of the camera was as follows: One wall had a tiny hole through which light was filtered in, and the wall opposite of this was completely blank.
As the light entered the tiny hole, an image of what was outside the box would appear on the blank wall. Because there was no film at this time, an artist would transfer the image onto a piece of paper by tracing it. Interestingly, the image would always appear upside down.
Function
The pinhole camera works the same way, only instead of an artist having to trace the image onto a piece of paper, the "blank wall" is now the film. The film contains chemicals that are light-sensitive and react to light. Once the reaction occurs, a negative that can later be turned into an actual photograph is created.
As time went on and cameras became more advanced, the mirror system was added in an effort to reverse the image before it ever reached the film, so that the images would not be upside down anymore. Also, lenses were added to create clearer images and to concentrate the light entering the camera. The amount of light that entered the camera was controlled by shutters. A photographer could also get a more accurate preview of the subject matter he was about to photograph by looking through the viewfinder, which also became more advanced but still served the same purpose.
Identification
The viewfinder is found on or in the camera and enables the photographer to look through it so he can focus on the subject that he wants to photograph. Though using the viewfinder works fine for subject matter that is in mid-range, taking photos from long distances or at close range can be a little more challenging.
Sometimes what the photographer will see through the viewfinder and what the camera actually photographs will turn out a little different. The internal camera prism located in the SLR camera is supposed to solve this problem, giving the photographer accurate results when taking photographs.
Effects
In order to change the direction of (or refract) light, the prism has a highly polished side. The prism is also transparent. Though most of us have heard of prisms shaped like triangles, which separate white light and turn them into a a variety of colored light, or a rainbow, prisms come in all sizes and shapes.
Roof pentaprisms are the prisms that are created inside the camera. These types of prisms are capable of changing light from left to right. The roof pentaprism is a very important part of the SLR.
Significance
Once light enters the lens in front of the camera, it will travel toward the back of the camera. A mirror, which is in place at a 90-degree angle, will reflect the light before it reaches the back of the camera. This will enable the light to point toward the camera's top. Before hitting the camera's prism, the light will have to go through a condenser lens and a filter screen.
Once the light makes contact with the prism, it is refracted down toward the front of the camera at a 45-degree angle. It then hits yet another prism and the light's direction is changed once more; it is now directed toward the back of the camera and will then go through the viewfinder.
This process allows the photographer to see the image he is looking at as it appears through the camera. In order to allow light to strike the back of the camera, the mirror is automatically moved. Incidentally, the back of the camera is where the film is kept. This is how a picture is made.
Tags: back camera, through viewfinder, back camera mirror, became more, became more advanced