Metering modes basically decides how your camera determines what the correct shutter speed and aperture should be, depending on the amount of light that goes into the camera and the ISO.
There are three main metering modes:
Matrix or Evaluated Metering: Matrix Metering or Evaluative Metering mode is the default metering mode on most DSLRs and Mirrorless Cameras. The principle is simple for this metering, the sensor determines the brightness of the scene over the entire image. It tries to do its best by analyzing the different brightness’s of your scene.
Center Weighted Metering: Center-weighted Metering evaluates the light in the middle of the frame and its surroundings and ignores the corners.
Spot Metering: Your camera only measures the intensity of light from a small circle in the center of the scene. Continue reading Chapter 7: Metering And Metering Modes – The Ultimate Beginners Photography Guide