There is no such thing as ‘correct’ exposure; what is deemed correct depends on a subjective judgment. Your camera might give you detail in a backlit subject when you are looking for a silhouette. You might want a darker sunset shot, or a lighter snow scene. But with a little knowledge and experimentation you camera will deliver what you want to achieve.
All this is possible using exposure compensation. This feature usually offers the option of up to ±2 stops compensation so that you can lighten or darken the image. Plus (+) compensation gives extra exposure, making the image lighter. Minus (-) compensation gives less exposure, making the image darker.
The best technique is to take a shot without compensation first. Look at the image that comes up on your camera’s LCD display. Is it what you want? If not, go to the exposure compensation option and make an adjustment. Take another picture. Keep making adjustments until you get the result you want.
Getting the exposure right in the camera will give you better results than trying to adjust the brightness or darkness of the image on your computer. It is always good practice to get the best results you can with your photo, so that any adjustment you do on your computer is from a good original shot.
When you move from sunlight to shade, or from tungsten lighting to fluorescent illumination, your eyes automatically adjust so that white objects still appears to be white.
Canon has built this flexibility into its digital cameras with a feature called ‘Auto White Balance’. This looks at the highlights in the image and processes the image’s colour to make these areas white. All the other colours fall into to place to give a faithful reproduction of the scene.
However, scenes with a strong predominant colour can fool the system and you will see a colour cast on the image. You can overcome this by using a white balance setting that suits the lighting conditions – daylight, for example, or cloudy, flash, tungsten or fluorescent. You need to remember to change the setting when the light changes, though.