In photography, the direction of light falling on a subject or scene can create a mood, control depth perspective, and enhance or diminish subject detail. Knowing this, we can often improve our pictures by changing our shooting angle, or arranging to shoot at a time when the direction of light will give us the desired lighting effect.
As a rule, it's a good idea to avoid front lighting, or light coming over the photographer's shoulder. This type of lighting tends to produce a flat, two dimensional effect; shadows are very weak, with little separation between foreground and background. In people shots, the subjects are forced to squint and screw up their faces. We've all seen these pictures, and they're not very flattering to the subject.
Light coming from a forty-five degree angle is much better. With shadows falling to one side, foreground and background are separated. This creates a nice modeling effect, and facial expressions are much more natural. Combined with a hazy or cloudy bright sky, excellent informal portraits can be the result.
The results can be even better if informal portraits are taken during the early to midmorning hours, or mid to late afternoon. The warmer lighting caused by the atmospheric filtration of the cooler blue light waves can result in very dramatic photos.
Portraits taken early or late in the day with ninety degree sidelighting can be even more striking. One side of the subject's face will be strongly lighted, and the other side, bathed in shadows, will be lacking in detail. On near subjects, sidelighting adds to the three dimensional effect by separating the foreground from the background.
Sunlight coming from a forty-five degree angle is great for scenery shots, too, especially if the light is also shining down on the scene from a forty-five degree angle. This is called forty-five forty-five lighting, and is also excellent lighting for portraits.
Ninety-degree sidelighting is good for close scenery shots, especially scenes in which texture is a factor, such as on water or sand dunes. Sidelighting is not very desirable, though, for distant scenics. Shadows obscure detail in the scene to too great an extent.
When using sidelighting, direct sunlight falling on the lens can produce lens flare. To avoid it, shield the lens from the sun, or use a lens hood on an SLR. Lens flare can produce some interesting effects in pictures, but it's usually better to avoid it if possible.
For detail in the shaded areas of sidelighted subjects, increase exposure. If your camera has exposure adjustment, increase exposure +1, or use the backlight button, if one is available. Otherwise, aim the camera at a dark area of the subject and press down part way on the shutter release to lock in the exposure, then recompose the shot and shoot.
For even more dramatic effects, use backlighting. Here, the light source is coming directly toward the photographer. To get some detail in the subject, set the exposure adjustment dial at +1 or +2 or point the camera toward a relatively dark part of the scene and press down part way on the shutter release to lock in exposure. For a strong silhouette effect, point the camera at a bright part of the scene, such as the sky, and don't make any exposure change. Again, lens flare can be a problem. Because of the possibility of lens flare and the unpredictability of exposure, backlighting is a little tricky, but you'll be greatly rewarded when it works, and with a digital camera, you can check it out.
Backlighting can produce very effective shots of open water, especially if the sun is low on the horizon and you can capture the reflection of the sun as it glistens on the water. Also, striking translucent effects can be obtained by shooting leaves, foliage or flowers with backlighting.