What is Exposure Compensation and when do I use it?
Almost every digital camera sold today comes with a wide variety of automatic shooting modes, where the camera decides every setting for you. This is a great way to start taking photographs, since a full understanding of the many options available to you as a photography enthusiast is not a requirement to taking pictures. Understanding aperture and shutter speed is an integral part of taking your photography to the next level, but if you are not taking any photographs at all, it does not matter how much technical knowledge you may or may not have.
Regardless of how advanced camera's internal computers get, there will always be times when the camera does not correctly expose the image. In photography, "exposure" is the term used to evaluate whether or not the image is too bright or too dark. A correct exposure means the picture is pleasing to the eye, and the subject of the image is identifiable. With the practically unlimited amount of variation in lighting that exists both in nature and artificially, it is impossible for the camera to always get the exposure just right every time. It is easy to settle with a poorly exposed picture, but it will always be disappointing when you realized you missed that special moment because of an error in exposure. Taking some control away from the camera and putting it into your hands will alleviate some of those camera miscalculations.
Exposure compensation is an easy way to correct for improper exposure. It is a "sliding scale" found on most digital cameras, usually indicated with a "plus/minus" sign and a sliding scale, usually ranging from -2.0 on the left to +2.0 on the right. There will be an indicator on the scale that shows where the exposure compensation adjustment is. Usually it is in the middle, at 0. This means the camera will make its exposure and take the picture with no input by you the photographer. In simple terms, adjusting the exposure compensation slider makes the next picture you take darker or lighter. It is forcing the camera to adjust is calculated exposure darker or lighter. You are not setting the actual exposure settings, that is still left up to the camera's computer, what you are doing is telling the camera that you are not completely satisfied with its calculations and adjusting them slightly.
"An example of the exposure compensation on a digital camera. In this case, a Canon A590IS."
If you bring the indicator on the exposure compensation scale to the left, towards the negative numbers, it will make the next picture darker. Let's say you take a picture of a person sitting in front of a dark background. The camera might see all those dark colors and try to make them properly exposed, but this will make the person in the resulting picture way too bright. To "force," or compensate, the camera to expose the person properly, bring the exposure compensation down below zero. The correct amount will be dependent on the scene, and experimentation is definitely encouraged.
"The image on the left was the exposure that the camera calculated for this scene. The camera wanted to make sure the walls of the tunnel were exposed properly, but as result, the sculpture at the end of the tunnel in daylight is very bright (over-exposed). By dialing down the exposure compensation to about -1.0, I was able to force the camera to darken the exposure."
Conversely, if you are photographing a person in front of a very bright background, say a sunny sky, the camera might see all of that bright light and try to make the picture properly exposed, and you will end up with a dark subject. Dial the exposure compensation up to the positive numbers, and the camera will make the next exposure brighter.
Taking control over your pictures is a process that does not happen over night, and involves lots of testing and playing around. Every camera behaves differently, so there is no universal setting that will work in every situation. By not settling with too-dark or too-bright photographs, you will dramatically increase the amount of usable pictures you get, and won't have to wonder what that great shot would have been like if it was only exposed properly.
Joshua Lehrer | Website
Josh is a recent graduate of the Advertising Photography program at the Rochester Institute of Technology. His career started in the NJ/NYC area where he worked as a freelance photographer, writer, and consultant. He also worked as marketing coordinator for a large photography retailer. He currently resides in South Florida, where he continues to be heavily involved in the photography industry.