Flash Lighting is used in situations when there is not enough of natural light.
It consists of the main light, fill light and a background light.
Main light is the strongest. It is set up first, 45 degrees away from the camera. The rest of the flash lights are subject to the main light.
The main light defines:
- size and shape of an object
- color or mode (black and white photo) 3
- persistence of shadows which play an important role in creating an impression of a dimension
- shape and size of the bright surfaces
- contrast of the shadows (strong, medium or soft shadow)
The right exposure is defined according to the main light.
Front Light or Fill light
Front light is set on the opposite side of the main light. It controls a shadow density. To reduce the strength of the shadows we use light reflectors. Advisable is to make sure that the main and the fill light do not have the same intensity because in that case the object on the photograph will not have any shadows. Generally, that's not the desirable effect. Contralight It's used to accentuate hair. It also separates the model from its background and the object itself gets more of a volume to it.
Sometimes it's necessary to light up the area behind the object. To do so we use a background light. If the object of interest and the background are the same color, background light can help highlight the shape of the object itself. When setting up any kind of lighting (photo or video) it’s important to follow a few specific steps.
First, set up the main light, then the fill light, and at the end, the background light. It’s done this way because if we would turn on all the lights at the same time, we would not be able to recognize which light is dropping which shadow. An affect like that is called a "stadium" effect.
When setting up the lights make sure to place them behind the camera to avoid its shadow falling on to the object of interest. The further the light is the weaker it gets and its strength falls each square distance so the exposure needs to be longer. That means: If for one meter distance the exposure needs to be one second long then for twice longer distance the exposure should be four times longer, for three times longer distance the exposure should be nine times longer and so on…