Basics of a digital camera

Author: Gaurav Birla August 25, 2010 No Comments

Talking about are digital camera, dSLRs or any other type of camera, the mechanism of capturing images is almost the same. We will be discussing in detail how a dSLR works and how it differs from a film camera.


 A camera is a simple gadget that captures light and records it on the storage medium (film, memory card). The common components of camera are the lens, shutter, image sensor, viewfinder and a mirror. Now let’s discuss what roles these components play and how image is captured.

  • Lens– Lens is an optical component of a camera and the function of lens is to focus the light coming from objects in the frame on the image making component of the camera. The angle of view of the camera is also defined by the type of lenses which is being used. Lens also defines what kind of optical distortions will be present in the image. A good lens should be clear from any kind of defects such as chromatic aberration, scratches, fogging etc lenses are the primary elements that help you define your compositions; how much area you want to cover, what kind of feeling you want to associate, how much depth of field you want to create.
  • Shutter – this is the component of the camera which restricts the light from falling onto the image making component when it is not required. When the shutter opens the light enters the camera and falls on the image making component and when the shutter closes its stops the inflow of light completely. The life of a camera body is also measured in shutter cycles. Every camera manufacturer defines that for how long a camera body is supposed to work properly in the unit of measurement is the number of times shutter can be used.
  • Viewfinder – viewfinder allows the photographer to look through the lens and compose and frame the picture. In case of SLR camera, the viewfinder shows exactly what will be visible to the image making component and finally will come out as the image. This gives a very clear idea about the framing of the photographs. Depending on the manufacturer, what you see in viewfinder can be different in terms of markings, grid or other elements which help you in composing your photographs. Normally a viewfinder will show you markings off the places which your camera uses for autofocus. Sometimes gridlines showing the rule of thirds are also visible in some cameras. A viewfinder can be optical as well as electronic. If the viewfinder directly shows you the coming right using glass and mirror elements, then it would be an optical viewfinder. In new cameras, especially in point-and-shoot cameras, electronic viewfinder is found. Electronic viewfinder is actually a small screen inside the camera that draws the image. Generally electronic viewfinder is providing you much more information and compositional guide elements like gridlines etc.
  • Mirror – this component allows the light which is entering the camera to divert and go to the viewfinder so that photograph can have a look when the exposure is not happening. Once the Mirror is lifted the same light which was coming through the lens will fall on the image making component, starting the exposure. During the exposure viewfinder will not show anything.
  • 540px-Ccd-sensorImage making component/image sensor – this is the main component of the camera which records the visible light and creates images. The resolution of the final picture depends on the image sensor. The number of pixels is defined by how many image sensing components or pixels are present on the sensor itself.

To control all the processes and to do all the complex calculations cameras have are built in processor. So in a way cameras are much like a small computer which does all the calculations, decides all the settings, takes the picture, store the picture and can also preview it.

Nowadays, the digital cameras and dSLRs have advanced is so much that they are able to take a photograph in almost any kind of situation, which was not the case with early cameras.

Tags: , , , , Tips and Tricks

Leave a Reply