ok I’ll bite. So based on the sensitivity of the sensor (ISO) the meter will see the amount of light and determine the optimum amount of light to properly expose the sensor. The amount of light is controlled through adjustment of the aperture of the lens and shutter speed. The sensor is designed to render the proper exposure based on all objects in the universe being 18% reflective gray. We know that’s not the case so we make override adjustments to the aperture and shutter speed. We also will use the meter reading to determine our desired combination of shutter speed and aperture to gives us a faster or slower shutter speed; or more or less depth of field while still providing the sensor the proper amount of light to make the exposure. As cameras and their meters have gotten more sophisticated, the electronics attempt to make some of those adjustments decisions for us. As long as we understand what the camera is trying to do and how it “sees” we can step in and make the changes to capture the image the way we want.
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