Automatic exposure is a wonderful tool to have, and is very accurate in most shooting situations. However, there are certain conditions in which auto metering can fail. When your camera “reads” the scene to determine proper exposure, it measures reflected light from the scene. The camera is looking for a neutral gray (called 18% gray) because it’s not too bright and not too dark. This works just fine in most situations, but nothing is perfect.
When is the camera wrong about exposure?
If your scene is mostly dark, such as a black cat against a dark background, the camera will be fooled into overexposing the image. On the other hand, if you’re shooting a snowy landscape, the camera will underexpose your image and the snow will look darker than it should. If you are taking portraits with the sun positioned behind your subject, the camera will expose the background properly but your subjects face will be too dark.
How can I override the auto exposure?
If your camera isn’t producing properly exposed images, there are a few options. You can use spot-metering, which takes a reading from a tiny area that you can move around, as opposed to averaging the light in the entire scene. This is very useful when someone is backlit or has a spotlight shining on them. Using exposure compensation is another good option. You can tell the camera to over or underexpose the scene without changing the way it reads light. This would be useful if you’re trying to capture an exquisite sunset. The camera will try to keep everything well lit in the scene, including the landscape. If you turn down the exposure compensation, you’ll be able to capture those deep red and orange colors that look so beautiful to our eyes. The landscape, in turn, will appear as a dark silhouette.
Once you get comfortable with how exposure works, you can turn the camera to manual exposure mode. Manual exposure gives you the greatest control over how your image looks, and it is a lot of fun to experiment with by trying different things!
Stop in any location and we can show you some more tricks. Also, you can take our Exposures class to get a little bit more comfortable!
-David Broome, Creve Coeur Superstore on Olive