It is important to know how your digital camera's light meter work if you want a proper image. Metering system is more or less control of aperture and shutter speed of the camera settings and it's based on the ISO speed and the image of lighting conditions. The metering usually includes spot, the zone evaluative or matrix, partial, and center-weighted metering. It will help your end results if you understand these options. If you want to get more about the light meter then you can hop over the link.
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Incident and reflected light
All light meter in a camera that is a little flawed from the start since the reflected light is the only kind that they can measure. This means the camera has to guess how much light is actually shining on your subject. If every object reflects the exact same amount of incident light it will not cause problems.
However, all the objects reflect different amounts of light. Because of this, the camera light meter is standard and they base them on how much light middle gray object will reflect. When the camera is pointed at something lighter or darker than the color is gray meter cannot really calculate how much light is reflected and produces pictures that are more or less bright.