What is 'exposure compensation'?
During my short course delivered from the Photography Institute, I was asked to explore 'exposure compensation'. Admitted, even after using cameras and teaching digital photography for well over a decade, I knew very little about the benefits of exposure compensation and how it can effect your images.
In short, exposure compensation allows you to override and adjust the exposure values set on your camera. In Automatic Mode (A) and Program Mode (P), the DSLR will automatically adjust the setting for optimal exposure, however, if you set the mode dial to M (Manual) or AV (Aperture Priority), you can dial up/down the exposure levels. This can be done by pressing the AV button with "+-" symbol (on a conventional Canon DSLR), and rotating the main dial left (to decrease) and right (to increase).
If you believe the setting requires the need for exposure compensation, increasing the compensation level will make your image/subject lighter and decreasing the compensation will make the image/subject darker.
How is this useful?
When taking a light reading and measuring for correct exposure, the camera may not always be accurate, or your subject may be too bright/dark against the background. Figure One is a good example of this, as the camera is correctly exposing the background, however, the main subject is too dark.
By adjusting the 'exposure compensation', in this case, by dialling it up to 3, the exposure is much more balanced and the figure in the foreground can be seen (see Figure Two).