If you agree that light is one of the key elements that differentiate a good photograph from a snapshot, then it’s necessary to learn and understand proper exposure. Believe it or not, there was a time when cameras did not have built in light meters, let alone automatic exposure. In those Jurassic-era days, photographers either used a hand-held exposure meter or relied on the data sheet that was packaged with each roll of film, providing basic exposure guidelines for taking photographs in bright sun, hazy sun, or cloudy conditions. The other widely used exposure method was based on the film’s ISO rating and the aperture f/16 aka the “Sunny 16” rule that is just as valid today as it was back then. Here’s how it works: To take a photograph in bright sunlight, the camera’s aperture was set to f/16 and the shutter speed is whatever comes closest to the ISO number. For instance, if you were using 125 ISO film, a sunlight exposure would be 1/125th of a second at f/16. The correct exposure for 400 ISO film would be 1/400th of a second at f/16 but since most cameras don’t have a 1/400th shutter speed, the closest speed of 1/500th was used.
The ability to tweak the exposure, even with today’s sophisticated cameras, can make or break your image quality and content. I’m always surprised at the number of people who don’t care about correct exposure, using the already worn-out cliche, “I’ll fix it later in Photoshop.” When exposure is concerned there’s only a partial truth to this statement. Adobe Photoshop has become a favorite crutch for sloppy camera work but you still need to be careful in the arena of proper exposure. A digital image that is too far over or underexposed cannot be completely saved with image editing software. Please re-read the last sentence.
You can make minor adjustments to the automatic exposure settings while shooting, including using the any of the different metering patterns that are available in the camera and maybe even pull out a hand-held meter from time to time. My favorite tool for tweaking exposure while using one of the camera’s automatic modes is the exposure compensation button. You can shift exposure to satisfy your creative needs to slightly over or underexpose the image by using the camera’s exposure compensation button that’s usually indicated by a button with plus and minus signs. It’s adjusted in positive or negative directions by some kind of wheel or control and while I hate to be the one to break it to you you’re going to have to read your camera’s manual to find out how your camera accomplishes this function. There are as many possibilities as there are camera models so give it a try the next time you shoot. Don’t just accept the camera’s automatic exposure (and then complain about it,) use exposure compensation to make it more than just another snapshot.
Joe Farace is author of “Studio Lighting Anywhere” that’s available from Amazon and your friendly neighborhood book or camera store.