Model: Erin Leighton
To learn how to use exposure compensation to change the brightness of your exposure
Time: 10 minutes
Skill level: Beginner
Kit needed: D-SLR
Your camera’s metering system plays a vital role in picture-taking. It works out how much light should enter the camera to make a correct exposure. Be warned, though: it’s very clever, but it’s not completely foolproof. The problem with metering is that it takes an average reading (either of the entire frame or part of it, depending on which metering mode you’re in), and this reading is assumed to be a midtone, halfway between white and black.
More often than not this assumption comes out right, but the metering system can struggle when a frame is dominated by areas of extreme brightness or darkness. For example, imagine a person standing in the snow wearing a white coat. The frame will be dominated by whites, but your metering system doesn’t know that it’s snow, all it detects is overly bright tones. So it does what it’s designed to do, which is allow less light than into the camera in order to average out the scene. The result could be an underexposed face. On the other hand, imagine a person standing under a spotlight in a dark room. This time the metering may be tricked by the large expanse of black into assuming the subject is darker than it really is, and overexpose the face.
It’s all about portions of the frame. Your camera can’t always work out what the most important portion is – but you can. The question is, if the camera gets it wrong, what can you do about it? The solution is exposure compensation. Found on all D-SLRs, this feature lets you dial in more or less light as needed. Here’s how…
STEP BY STEP: Control brightness
1 ON THE DARK SIDE
When shooting your subject in shade against a brighter backdrop your camera’s metering system may struggle. In the inset image on the left you can see that the result of shooting from dark to light when relying purely on matrix metering is an underexposed subject.
MAKE A PREDICTION
The more you try it, the easier it is to predict in advance when exposure compensation might be necessary before taking the shot.
This’ll save time and minimises dud shots. Portrait photographers, for example, will often dial in a 1/3 stop overexposure as standard when shooting people outdoors, just to lift the face for a bright, clean feel.
2 GIVE IT ONE
If you don’t want to leave your subject in the dark, now’s the time to try exposure compensation. Most D-SLRs have a dedicated exposure compensation button on the top plate. Hold it down and flick the back dial to add in more light – here we’ll try +1 stop.
As an alternative to exposure compensation, try spot metering and meter directly off the subject’s face for accurate exposures in any lighting conditions
3 ADD MORE LIGHT
At +1 stop we’ve lifted the subject, but perhaps not enough. So we can try adding in a little more light. We took it to +2.3 for our main image here. This correctly exposes the face; it blows out some of the background detail but that’s fine, we can’t have it both ways.
4 CHANGE THE MOOD
Exposure compensation gives you a huge degree of control over the mood of your shots. Here, with the flick of a dial we go from a moody silhouette to a bright, airy portrait. Just remember, reset the dial when you’re done or it might trip you up next time you pick up your camera!
5 LIGHT TO DARK
When the background is darker than the subject we have the opposite problem: our metering system may overexpose the face. We moved our model into the light and shot into a background of shade. When shooting in sunshine like this, tilt the face upwards towards the light.
6 TAKE IT DOWN
As you can see from the shot on the left, the large dark patches in the frame have fooled the meter into thinking we need more light than we really do, resulting in an overexposed face. So we dial in -1 stop of underexposure and the skin tones look much nicer.