The light patterns emitted are obtained in a photographic film activate a chemical or electrical sensor in the storing material. This is usually done through a camera lens which is highly sensitive.

The camera is the image forming device. The electronic image sensors or a photographic film is the recording medium. Nowadays digital cameras are also available which have electronic medium as the storing medium.

The basic principle of the camera is that, it controls the amount of light and time of the exposure of the camera to the outer world by using a lens. When there is sufficient light, then we can form an image on a film. This raw image can then be developed to obtain a real time original image.

Movie camera is another type of camera in which the total movements are captured and not only the still. The basic idea behind the movie camera is that the data are captured in a sequence of photographs with no delay in between them. This forms a moving frame which is often captured with the voice.

To ensure that we obtain a sharp and clear photograph, we have to make sure that we adjust the camera either manually or automatically. Below are some of the controls and its descriptions.

Focus is the adjustment that is made to bring the desired area or the desired part to the sharpest point possible. This is usually done manually, but this is also done automatically in some latest digital cameras.

Aperture can be referred to as the adjustments of the iris. It is also known as the f number. This number usually controls the amount of light that will pass through the lens. The aperture has also known to have some effect on the focus and the depth of the field.

The controls over the speed of the shutter with which it closes and opens are called as shutter speed. This is usually in the speeds of milliseconds. This is the time of which the imaging medium and the light are exposed to the storing medium.

The white balance is a special feature in the digital cameras that is used to ensure that the white light is captured as it was in the real medium so that the colors that are in the imaging area appear naturally.

Metering is the measurement of the amounts of the exposure of the light. This is done manually so that the bright light areas and the shadow regions are captured according to the photographer's wish.

Auto-focus point is an additional feature that is employed in many of the new digital cameras to ensure that the focus is done so that it satisfies the photographer's wish. Nowadays multiple auto focus points in the view finder are also available.