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Get the Correct Exposure

October 3rd, 2008 by corina.fiore

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Photography.

Photo.

Light.

The most critical aspect of good photography is capturing an image with the proper exposure and proper lighting. Without proper exposure, backgrounds can be overblown while the subject is underexposed, freshly fallen snow can appear gray, and the beautiful pinks and purples of a sunset can be lost in an overexposed sun. However, with a little knowledge and preparation, every photograph can have proper exposure, allowing the subject to shine.

The Problems

Your camera has an on board light meter that is used to calculate the correct film exposure. In order to achieve this, the meter “assumes” the average reflectance of light of the subject to be 18% gray. In other words, the meter doesn’t get “thrown” by the harsh blacks and the stark whites in a scene and set the speed and aperture to severely over/underexpose the photograph. Instead, the meter averages all the colors in the setting to a middle gray. Your photographs, therefore, are not extremely over or underexposed, but subjects often lack the “pop” that you may intend.

Notice how gray the snow looks in the photograph at the top of the post. The meter “read” the snow and adjusted the exposure to middle gray.

Another problem that occurs with exposure is when there is a gradient between light and dark. For example, when you take a picture of a person in the shade (which you may do to avoid harsh shadows), the subject can be back lit. Unless you properly meter this situation, the subject may appear underexposed.

The Solutions

Know your camera. Many cameras allow you to change from a matrix meter, where it meters the entire scene, to a spot meter where it meters a small portion of the scene. This is helpful when you have a distinct subject that you are trying to expose properly.
Move close to your subject to meter it properly. You can always recompose the shot from farther away.
Many cameras have an exposure lock. Learn how the exposure lock works in your camera. After you meter the subject, use the exposure lock to lock in the shutter speed and aperture. Then recompose the shot.
Use an 18% gray card. These can be purchased at any camera store. If you meter off the 18% gray card in the same lighting conditions as your subject, your meter exposed 18% gray properly, rather than assuming the entire scene is 18% gray.

white-snow

This photograph was taken the same day, but I metered off an 18% gray card. Notice the difference in the color of the snow.

Be careful not to meter your own shadow.
If the subject is lighter than 18% gray, pone up a stop or two while maintaining the shutter speed. If you subject is darker than 18% gray, close down a stop or two while maintaining your shutter speed.
Bracket your shots. In other words, use the camera’s meter readings, then re-shoot as you open up a stop or two and close down a stop or two. This way you get a wide range of exposures and you can use the best of the bunch.

By using these techniques, you will be on your way to getting the correct exposure and becoming a better photographer.

Corina is a former science teacher staying home to raise her two imaginative, active, and wicked smart children. Contrary to what the last line suggests, she is not from Boston or Canada. She is a mom, photographer, teacher, outdoor enthusiast, sarcastic, and down to earth woman. You can find her weaving her tale and small tales at Down to Earth Mama .

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