Lights illuminate objects. If your scene contains no lights, then it renders entirely black (unless, for example, you are using shaders with incandescence). You can also use lights to create special optical effects (for example, halos, lens flares, or fog).
There are seven different types of lights. There is also a tool for creating default lighting for a scene.
Point lights are like incandescent light bulbs—they cast light in all directions. See Render > Create Lights > Point .
Spot lights cast light in one direction only, emanating from a point in a cone. See Render > Create Lights > Spot .
Directional lights are directional source lights that have color, intensity, and direction, but no obvious source in the scene. See Render > Create Lights > Directional .
Ambient lights are similar to point lights except that only a portion of the illumination emanates from the point. The remainder of the illumination comes from all directions and lights everything uniformly. See Render > Create Lights > Ambient .
Area lights are two-dimensional rectangular light sources. See Render > Create Lights > Area .
Volume lights define a closed volume in which objects are illuminated, and nothing outside the volume is directly illuminated by the light. See Render > Create Lights > Volume .
Linear lights are one-dimensional line-like lights similar to fluorescent tubes). SeeRender > Create Lights > Linear .
The Create defaults tool sets the default lighting for a scene. When you select Render > Create Lights > Create Defaults , an ambient light and a directional light are automatically created. Their orientation and position are pre-defined and their values are based on each light’s default options.