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
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
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
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
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.