Taking Better Digital Photos With Auto Settings Part 1:
Autoexposure

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Quick Photography Tip
Keep an eye on the light. It is constantly changing

Using the auto mode on a digital camera gives you a point and shoot camera that allows you to concentrate on the subject while the camera makes the necessary settings to give you a well exposed and properly focused image.

But like most automatic features, knowing how they function will help you keep the camera from getting fooled in those special situations that often yield the most dramatic photos: including when your subject is backlit or off-center.

Understanding Auto Exposure

Auto Exposure controls the amount of light that is used to expose the camera's image sensor. It does this by adjusting the aperture and the shutter speed.

Proper exposure is basically determined by averaging the amount of light needed to produce an image with good highlights, middle tones, and shadows.

The camera has a built in light meter that evaluates the total amount of light reflected from the subject. It then averages this light and sets the correct exposure.

Digital cameras can have more than one type of metering system however, so it is important to learn how your particular camera meter measures light as well as any options to change the way it does this.

Averaging Meter System

An averaging type of metering system is one of the most common. With this type of system the meter reads the entire scene then calculates the exposure based on the assumption that there are a few highlights, a few shadows and a full range of mid-tones.


Very often this type of metering is center weighted, which means it gives more emphasis to the center or foreground area of the image than to the other areas.

If your main subject is in this part of your photo, you should get a properly exposed image. But if you have lots of bright area in the scene, such as snow or a bright sky, this method may not be correct. A lot of black area will also cause the meter to render an incorrect exposure.

Try this exercise to learn how your camera works:

Turn off your flash and make certain the averaging system of metering is selected. (This will likely be the default setting on your camera, so you won't need to change anything).

Choose a subject that has a good balance of light to dark areas in it and make your first shot. It should be pretty well exposed, with good detail in the highlight and shadow areas.

Next, place your main subject in front of a very light background such as a bright sky or a well lit white wall and take the picture. The subject will likely be too dark. The meter will reduce the exposure since it will average the total light in the scene. As a result mid-tones become dark, and shadows turn black.

Now place the same subject against a black background and the opposite will occur. The meter will allow more exposure and the subject will appear too light, and the lightest areas will become pure white, loosing their detail.

So, how do we control this type of metering to get the results we want?

Most digital cameras come with exposure lock. This allows you to lock the exposure by pressing the shutter release button halfway down and holding it there while you recompose your picture.

Experiment with this by placing a person in front of a bright background, such as a white wall or bright sky. Try turning the camera vertical, filling the majority of the frame with the subject.

Lock in the exposure. Now turn the camera to a horizontal composition with your subject off center and take the picture. Your subject should be well exposed.

TIP: Often the focus and exposure are both locked when the shutter release button is pressed half way, so this technique is limited. As long as the subject is about the same distance from the lens in the final composition as it was when you used the lock function then you will be OK.

There are many additional controls for exposure including White and Color Balancing, Flash and Lighting featuring: Red Eye Reduction and Fill Flash, plus a look at Auto Focus and taking Action Shots. We'll explore theses topics in the rest of our series: Taking Better Digital Photos With Auto Settings PARTS 2-4.

If your camera doesn't have these options, you will still want to know what they are, especially if you want more creative control over your photography, so you can choose your next digital camera for the features most important for your photography style. These options can be extremely important to getting the results you desire.


About the Author

The Editors at www.TakeBetterDigitalPhotos.com are committed to bringing you the most useful information about the rapidly evolving field of digital photography from a hobbyist perspective. Visit the Quick Tips page for techniques you can use at your next event or photo opportunity.


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Taking Better Digital Photos With Auto Settings Part 2: White And Color Balancing
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