What is Camera Metering?

A camera's metering mode generally refers to the way the camera itself comes about the correct exposure for a picture. There are several different types of metering modes, including spot and multi-zone, and most cameras allow for an auto-metering setting that lets even the most novice photographers take advantage of the right exposure. Overexposing a picture can ruin it and underexposing can do just as much damage; by learning more about metering, you will know how to avoid both problems and increase your chances of beautiful and vibrant pictures to share.

Spot metering will focus on a tiny area of the overall picture. Many digital cameras are set to default on this mode, but this can be changed in the camera's settings. This takes one area of the overall picture to focus on, usually the center of the picture, and allows for the exposure to compensate for other areas of the picture that may be over or underexposed if actually focused on. Generally, your digital camera will pop up with a small box of the area being focused on so that you can see what focus your picture will have. More advanced modes allow for you to switch between multiple spots the camera determines would be good areas to spot focus on.

This is accepted at the most accurate form of metering. When the camera chooses an area, or you choose an area yourself, your camera adjusts and focuses in on the single area to block out other exposures that might be damage to the overall photo. Spot metering allows you to measure areas of light that might affect the subject of your photo. For example, if you are taking a picture of your kids, and your tallest son's face is being hit by sunlight from behind, spot metering allows you to compensate for the bright light and adjust that part of the picture accordingly so that all your children can be seen when the picture is actually taken.

Another form of metering, center weighted metering, occurs when more than 60 percent of picture is being focused on. More advanced digital cameras will allow the photographer to adjust what area is the main focus in regards to the edges of the picture. This feathers the entire metering throughout the picture instead of focusing on a small area that might be affected; this type of technique helps focus on the overall subject of the picture being accurately exposed as opposed to a smaller portion that might be effected.

Average metering and partial metering are two more forms of camera metering. Average metering takes the light source for the whole picture and compensates for its exposure. It does not focus on any one area and distributes the exposure evenly throughout the photo. Partial metering, on the other hand, focuses on a larger area than spot metering. It uses takes about 12 percent of the picture that is either very dark or very light and compensates to even it out during the exposure process. Partial metering is best used for dark or light edges outside the subject area of the photo itself. Some more advanced digital cameras can take multiple partial meterings at a single time or even allow you to choose what areas need the most attention.

Multi-zone metering is one of the more advanced forms of camera metering and is found on most modern digital cameras. It is sometimes known as matrix mode and was introduced in Nikon cameras over the last year and a half; it is generally the default settings on these cameras. The digital camera itself measures the intensity of light in the overall picture, combines the light results and then determines the best exposure as you are taking the picture taking all the guesswork out of having to do it yourself. Depending on the camera you are using, you may find this in excellent way to avoid over or underexposing your pictures.

Each camera stores a pre-determined amount of equations that determines what exposure to use. Multi-zone metering tends to focus on the central auto-focus of the picture, however, and this can change the dynamics of your photo if your eye was on another portion of the overall photo than what the camera chooses to be the central focus of exposure. Some of these cameras do allow the photographer to turn off the auto-focus setting and still use multi-zone metering, which allows them greater control over the subject of focus but it can also take away from the function of the auto-metering.

Learning how your digital camera reacts to different metering modes, especially the advanced multi-zone metering, is the most effective way to see how metering affects the overall outcome of your pictures. Taking the time to learn how your camera reacts will benefit your photography over time and give you the chance to capture some awesome shots that might have been missed if you over or underexposed your picture. Pull out your camera manual, read through the instructions and give the different metering modes a try to see the results.