Getting the right exposure is the oldest problem in photography and although modern auto-exposure systems bring you a lot closer, there are still lots of situations where they fail. In these cases, modern digital cameras offer some secret weapons that can save the day. These tools are the LCD finder or Electronic viewfinder, and spot metering -- the ability to measure the exposure for just a small part of the image.
Most point-and-shoot digital cameras have both of these, while the DSLRs have only the spot metering. These examples were shot with my Panasonic DMC-FZ28, which has both.
The first step is to learn to understand and interpret what you see in the camera's viewfinder. If there is any auto-gain setting for the viewfinder, as there is on the FZ28, make sure that you find it and turn it off. It will give misleading results. If your camera has an electronic viewfinder, use this instead of the LCD on the back of the camera, especially when outdoors. Then find where in your camera's menu system you can set the exposure to spot metering. When you do this, some cameras put a little cross in the center of the frame to show where the metering system is aimed.
One last thing. Look at the controls on your camera and see if there is a button to lock the exposure and/or the focus. If there is, make sure that it is set so that it locks the exposure. On the FZ28, this button is on the back of the camera and it's marked AF/AE LOCK. Now we're ready to proceed.
Here's our first example. While strolling through Washington DC, I saw this picturesque streetlight with a tree behind it. Let's try the tools built into the digital camera and see how they can help.
As I said at the beginning, in digital photography you can expose for the highlights and develop for the shadows. A burned out highlight is unrecoverable, but there's always detail hiding in the shadows.
Some cameras, like the DMC-FZ28, with improved image quality at the higher ISOs respond better to this, since boosting the shadow detail is equivalent to boosting the ISO of the film in those areas.
In LightZone, I used the "Relight" tool, since this gives you a quick way to see the shadows. From there, you can tweak and fiddle to get the final picture.
Most of the other photo editing programs have similar tools. If not, you can play with the "Levels" tool to raise the detail in the shadows. The thing to remember is that there's always detail hidden in the shadows, but a burnt-out highlight is forever.
Learning to use spot metering, along with being able to interpret what you see in your camera's electronic viewfinder, and using the button to lock the exposure, will help to guarantee getting the right exposure in all sorts of tricky lighting situations. Use this technique when shooting a picture of the moon or a sunset or a situation where the light is behind your subject. Experiment with these tools and you'll boost the percentage of correctly exposed pictures your digital camera delivers.