Cameras are electronic devices used for recording images, still images or motion images such as videos.
Simplified for the layman, the camera is a box that controls the amount of light that reaches a piece of light sensitive film on the other side inside. The very first cameras did not have glass lenses, they used a tiny hole to allow light into the box and to focus the image onto the viewing film or other surface inside.
Cameras of today have glass lenses to capture light easily and quickly and allow magnification of images. They also have a shatter that controls light from getting to the sensor. In fact the camera has evolved a lot from little beginnings, but it is still a box that controls the light reaching the film. As cameras have advanced, there are different types of cameras, each type suitable for a particular use.
Single-lens Reflex (SRL) Camera
This camera is characterized by the use of a semi-automatic moving mirror system which permits the photographer to see exactly what will be captured. Before the development of the SRL camera, cameras having viewfinders also had two light paths, one through the lens to the film and the other positioned to the other side called the rangefinder.
Most SLR cameras allow straight and laterally right viewing through use of a pentaprism located in the optical path between the reflex mirror and viewfinder. Light is reflected by a movable mirror upwards into the pentaprism, where it is reflected several times until it aligns with the viewfinder. As the shutter is released, the mirror moves away from the path of the light and the light shines directly onto the film.
The photographer can manually adjust the focus or it can be adjusted automatically by an auto focus system in the camera.
SRL cameras are generally more expensive than the other types of cameras, due to their internal complexity. They are however considered durable due to the materials used in its manufacture
Compact Digital Cameras
Compact digital cameras are the smallest and most portable cameras available today, they are designed for casual use and hence the name point-and-shoot camera. Most compact digital camera models consist of a retractable lens assembly allowing a thin camera to have a moderately long focal length and thus exploit a larger image sensor. They also have an automatic lens cover to cover the lens when retracted. Compact digital cameras are easy to use and are relatively affordable.
Low Light Cameras
Low light cameras are made for use in low light conditions. They have sensors that are very sensitive to light and make images look like a series of lines. There are two basic types of low light cameras: monochrome and color. Monochrome devices present images in black and white, while color devices present images in a range of colors. Low light cameras use several image sensing techniques. Charge coupled devices (CCDs), Complementary metal oxide semiconductor (CMOS). Analog and digital processing functions can be integrated readily onto a CMOS chip, reducing system package size and overall cost.
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