You usually depend on your camera’s built-in lightmeter for correct exposure. But sometimes the “right” exposure isn’t the best choice. Here are examples of when and how to get around it.

• Backlighting: When the dominant light comes from behind the subject,using your camera to take a reflected light reading of the entire scene will give you a bad exposure. Instead, take either a reflected or an incident reading (using a handheld incident meter) of the subject alone for the correct exposure.

• Silhouettes: To capture just your subject’s shape, with no details, meter only the brightly lit background to determine exposure, and let your subject fall entirely into shadow.

•  Halos: In extremely contrasty scenes, exposing for shadow areas will overexpose the highlights. For a realistic picture, you’d want to avoid this. But it can create an interesting halo around the subject, especially when you use strong backlighting or a softening filter.

Adapted from Studio Photography Essentail Skills , Fourth Edition by John Child (Focal Press , 2008; $30)