Exposure Compensation

Exposure Compensation

Exposure compensation is a feature that lets you tell the camera to make the image brighter or darker than what the meter recommends. It is marked as a plus or minus value, typically from minus three to plus three stops. When you dial in plus one exposure compensation, the camera makes the image one stop brighter. Minus one makes it one stop darker. In aperture priority mode, it changes the shutter speed. In shutter priority mode, it changes the aperture.

Exposure compensation is needed because the camera's light meter assumes everything in the scene is medium gray, also called 18 percent gray. A snowy landscape is much brighter than medium gray, so the meter underexposes it, making the snow look gray. You dial in plus one or two stops of compensation to make the snow white. A dark scene with a black dog against a dark background fools the meter into overexposing. You dial in negative compensation to keep the blacks looking black.

The exposure compensation button is usually marked with a plus and minus symbol and is located near the shutter button on most cameras. In aperture priority, turning the main dial changes the exposure compensation while the aperture stays fixed. In manual mode, exposure compensation does nothing because you control both aperture and shutter directly, and the meter is just a reference. Some cameras also have an exposure compensation setting in the quick menu or as a dedicated dial.

Using exposure compensation effectively requires checking the histogram. If the histogram is bunched up against the left edge, you are underexposed and should add positive compensation. If it is bunched up against the right edge, you are overexposed and should add negative compensation. Your camera's light meter might show zero, meaning it thinks the exposure is correct, but the histogram may tell a different story. Trust the histogram over the meter.

Bracketing and exposure compensation are related but different. Bracketing automatically takes multiple shots at different exposures, which you can later choose from or merge. Exposure compensation shifts the exposure of a single shot. If you want to be safe, set the exposure compensation to what you think is correct and also shoot a bracket around that setting. This is a common technique for landscape photographers shooting high-contrast scenes.