Snowflakes fall gently across the barren expanse of the frozen lake. The soft blanket of beauty leaves one almost unaware of the winter chill lingering in the shadows. The crisp air breathes new life into your body and soul. Camera in hand, you frame the scene, hoping to capture the magic and peace you find on this January afternoon. Click – a beautiful shot, but something not quite right nags at your inner being.
Exposure compensation exists as the antidote for that nagging feeling. Scenes that involve mostly bright content – like a lake covered in white and an overcast sky – are tricksters for even the most advanced camera systems.
Scenes dominated by snow often come out “grayish” and low contrast in the final image if the camera is left to its own judgment. When the camera determines exposure of the scene above, it “sees” a frame almost entirely filled with bright white snow and overcast skies. Because the camera reads the scene as overly bright, it sets a lower exposure to bring things back to a level it considers “normal” (17% gray to be exact, but that’s a story for a different day). So, although humans know that snow covered scenes are indeed bright white in most instances, the camera thinks this is abnormal and adjusts things accordingly.
Exposure compensation allows the photographer to tell the camera who is boss. Exposure compensation directs the camera to take whatever it thinks is the correct exposure and increase it or decrease it by a certain amount. In the case of snow, a camera meter will usually underexpose an image by two-thirds to a full stop (two thirds of a unit to a full unit of brightness). To compensate for the camera’s ill-advised ways, the photographer can hold down the Av/+- button while turning the main control dial to the right to add brightness/increase exposure or to the left to lower exposure.
To set exposure compensation at 2/3 a unit brighter (two-thirds a stop), the marker would be placed in the position shown at right.
For anyone wishing to experiment with exposure compensation, it is very important not to set the marker back to the zero/middle position when finished. Otherwise, the camera will continue to purposefully add or subtract the amount of exposure compensation to every picture taken until told to do otherwise.
To change the exposure marker back to zero in this case, the photographer would hold down the Av/+- button and turn the main control dial two clicks to the left.
Notice the differences in what the camera sets for exposure of the snow scene and what is created by using exposure compensation. The “bumps” of snow in the lower third of the frame are a more accurate white and contrast seems to be at a more appropriate level.
Important to note, however, there is nothing wrong with the left half of the picture – it simply gives a slightly different feeling which may be the photographer’s intent all along. Some may find the frozen portion of the lake in the middle third of the right half of the picture way too bright. It simply becomes a matter of personal preference. Perhaps splitting the difference to +one-third a stop exposure compensation provides the perfect compromise.
Only one way to find out … Keep what you like and disregard the rest. Just don’t ever stop experimenting.