Light is often overlooked, but it is critical to understand how it works in photography. The sensor is your canvas and the light your paint. The first job of every photographer is to get the light right. Photographers must capture the right amount of light, in the right amount of time, in the right way. In skilled hands, a camera is a paintbrush. The art of photography is literally the art of painting with light.
Angle - Light angle determines where the shadows fall in an image, and has a profound effect on revealing shape, or sculpting an image. If the light is coming from the same axis as the camera lens, the light will provide very even coverage. It makes the subject look flatter than you might expect. If it's coming from the side, one side of the subject will be well lit, with the other side in shadow.
Light angle have a huge impact on the mood of a photograph. For example, in a portrait lit from below, the light will cast shadows upward, creating a sinister effect. It’s similar to the flashlight effect commonly used to tell ghost stories around a campfire.
Quality - Light can be either hard or soft. Hard light casts sharp shadow edges. Soft light casts gradual transitions between light and shadow. Soft light is frequently preferred in portraiture and beauty photography. But hard light can create a great sense of drama, and is frequently used in cinema.
Shadow - Shadows can be intentionally cast into a scene to create interest or drama. Perhaps the most over-used cliché is shadow from window-blinds.
Highlight - Often, lights are placed behind and above or to the right or left of a subject to create glancing highlights. When the highlights create a light outline around the subject, it’s called rim lights. When the highlights are aimed at the hair, it’s called hair lights. Highlights can also be created with side, bottom, or even front fill light. Often, one or two highlights can further sculpt the shape of the subject, separating it from the background, and make it pop.
Portrait Lighting Tips - Try placing subjects near large windows. Windows create a large light source, which can mimic expensive soft box equipment and create beautiful soft light for portraits. If you're shooting outdoors at mid-day, the light will be hard, making shadows a problem. Try turning the flash on to help the harsh shadows or move your subject into open shade. A better solution is shooting as the sun comes up or just before sunset. Many photographers take advantage the softer morning or late afternoon light. It’s warmer and more flattering to the subject.