The main effect of exposure to have three components: diaphragm, exposure time and equivalent sensitivity matrix / film. Operation of these volumes is the whole art of photography. They can be fully regulated by the photographer in the manual mode (M) or by the camera in auto mode, and partly by man and partly by a semi-automatic camera in Tv mode, Av (Canon) S, A (Nikon), P, to be described later in this chapter. Currently, many professional photographers use the modes half automatic primarily because it save time, facilitate the proper exposure of the images and allows the photographer to achieve the intended effect. Of course, complete control over the photograph provides a manual mode, but in this mode, beginners may have trouble with the proper exposure images.

Semi-automatic mode allows you to use a parameter to achieve the desired effect, and the other is governed by the camera. Of course, the fastest mode is the full auto, but does not give us hardly any possibility of control over the image outside the framing, and turn on and turn off the flash. Some cameras also have an exposure control function by adding or reducing the so-called. plots (EV)-Exposure Value, or units in which exposure is measured. Increasing causes us to lighten the image, and reducing the blackout.