A digital camera has been equipped with a metering system as part of the camera software. In general, digital camera metering is the way the camera goes about getting the right exposure for a shot.
Back in the day, photographers had to determine their own exposure settings, and they would carry a light meter with them. Holding the meter where the subject of the photo was and facing the camera, the light meter would produce a reading that indicated to the photographer what the proper aperture and shutter speed should be.
The days of manual metering are over. And, even better, newer cameras are more sophisticated and better able to correctly determine the right settings because of the in-camera software.
With that in mind, there is still some knowledge required by the photographer. Cameras have come a long way and are pretty good at "guessing" the right exposure in most situations, but they simply do not have brains. That's why, in certain conditions, it is up to the photographer to decide whether the situation calls for special metering.
Three metering modes
The first metering mode is evaluative metering. This is where the camera will take into consideration all of the light in the subject area. With that information, it will set the aperture and shutter speed according to the built-in algorithm.
The second type of digital camera metering is center-weighted metering. In this method, the camera places more emphasis on the center of the frame, while it still "sees" the lighting in the entire frame. It is the center of the frame that determines the aperture and shutter speed.
The third type is spot metering. With spot metering, the camera calculates the aperture and shutter speed using just a small part of the framed area.
Setting the Metering mode
To set the digital camera metering mode camera, you will need to read the camera manual, but in high-end cameras, there is a place on the LCD read-out where the selected settings are displayed. By pressing the right button, you can activate the metering mode and change it by rotating the correct dial.
Most photographers set their camera on evaluative metering for normal situations. The second most common metering is partial, or center-weighted metering. This is when there is a backlit subject. Using regular metering would produce a very dark subject in your photo. This works very well with many portraits when the light behind the subject is bright.
Spot metering is used the least of the three, but there is a proper time for it. When the subject is fairly small in the frame and surrounded by bright light. The camera would be fooled into the wrong settings if left on either evaluative or partial metering.
Even with all these manual settings, it is possible to get a bad picture due to the lighting. Practice taking pictures in the toughest of lighting situations so that you are familiar with how your particular camera works. This way, you will have a much better success ratio.
There are still some very good photographers who use hand-held meters to determine the light and camera settings. However, they are becoming quite rare, not because it is a bad way to set up your camera, but because cameras are getting so good at "figuring out" the right exposure.