Overcast skies

The quality of light can be excellent on dank, dreary days. Rather than producing harsh contrasts between bright highlights and deep shadows, light filtered through a canopy of clouds is even and diffused. Contrasts are soft and subtle. Colors are rich and fully saturated. Bright colors that would ordinarily clash with each other or overwhelm muted hues become more harmonious and part of a unified image.

Scenes photographed on an overcast day usually work best when you move in close and fill the entire image area with shapes and colors, since the sky is often an uninteresting, washed-out gray or white. Sometimes, however, a bland sky can provide a plain backdrop that sharply sets off interesting foreground elements. But try to keep your horizon line relatively high so that there is more ground than sky, and, if possible, mask part of the sky with a foreground frame such as overhanging tree branches.

Even when the sky looks gray, it can still be bright, and when it is included in a scene, it can mislead your camera's meter into making an underexposure that silhouettes the foreground. Take your reading off the foreground or an 18 percent gray card.

The lighting on an overcast day is excellent for outdoor portraits. Its soft, diffused quality is always flattering because it gently reveals the contours of the face with faint, almost imperceptible shadows.

Fog and Mist

The soft, hazy atmosphere created by fog and mist can be especially effective in photographs because it obscures more than it shows. In fog and mist, the farther an object is from the camera, the more it seems to dissolve and merge with the murky background. Even a fairly cluttered scene, such as a forest, is greatly simplified. Only subjects close to your camera stand out, and colors are so muted that they look almost monochromatic.

Fog, like sand and snow, is a bright, high-key subject and can fool a light meter into calling for underexposure. The best exposure will frequently be one of two f-stops more exposure than what the meter says. It's usually best to take the meter reading off an 18 percent gray card or a middle tone in the foreground.

The best place to find hazy conditions is on or near bodies of water, and the best time of day is early morning, before the sun has had a chance to burn off the night's accumulation of mist. Look for strong, distinctive shapes, especially ones that stand out against the haziness as dark silhouettes. Because the lighting is usually dim, plan to use a high-speed film and, if you go out especially early, take along a tripod for the necessary long exposures.

Storms and lightning

Storms, especially electrical storms, are among the most spectacular shows staged by nature, and capturing them on film is challenging. Luckily, the most dramatic shots of storm clouds can be taken as the storm approaches or leaves. It is during these transitional periods that you can get striking contrasts between areas that are clouded and ones that are sunlit. Sunlight breaking through dark clouds or creating bright rim lighting along their edges is especially attractive. Since lighting conditions are uneven and rapidly changing at such times, be sure to bracket your exposures.

Lightning can usually be photographed only during the height of a storm. To protect both yourself and your camera, you should always take your pictures from a safe cover. It is next to impossible to photograph lightning during the daytime unless you are waiting with eye on the viewfinder and finger on the shutter. And even then you may miss it. You'll find it much easier to work and will usually get more dramatic results if you make a time exposure at night.

Set up your camera on a tripod and point it at the area of the sky where most of the lightning seems to be occurring. Set your camera's shutter speed dial on B. Then open the shutter using a cable release and hold it open until a bolt streaks out of the clouds. Be sure to work in a dark area and to pick a scene that does not include light from houses or street lights. Exposure is mostly a matter of guesswork. Bracket by making several time exposures at different apertures. A good starting point is f/5.6 with ISO 60 film. Holding the shutter open for too long causes an overexposure of the surrounding area. Heat flashes between clouds can also ruin a frame.

Rainbows

In the aftermath of a rainstorm, nature sometimes provides us with one of its most delicate visual treats, the rainbow. A rainbow is caused by particles of moisture in the air that act as tiny prims to diffract the light, breaking it up into a spectral array of wavelengths of different colors. The phenomenon is not limited to rain-soaked skies; it can occur any place where there is an abundance of moisture in the air. A waterfall, a public fountain, or even a morning mist will often sport a miniature rainbow when sunlight hits at the proper angle.

Rainbows are very transient, rarely lasting more than a few minutes. When you spot one, you have to act quickly. In composing your picture, the chief problem is usually trying to locate, on such short notice, foreground elements that will add interest to the scene. A rainbow alone is beautiful but not likely to be visually compelling. A foreground, such as sailboats, icy branches, or stone figures, provides a sense of place and completes the composition. In exposure, a problem can occur if a large expanse of relatively bright sky is included in the scene. In this case, it is best to take a reading off the foreground. Or, if you want to produce a greater saturation of colors in the rainbow, try underexposing one half-stop from the reading your derived from the foreground. On an automatic camera, temporarily reset your film-speed dial one ISO setting higher.