This is the fourteenth article in a series on "understanding your camera" that I am writing as I teach camera basics and camera operation to my children.
Here is a very practical example demonstrating why it is important to understand your camera. As previously described in a blog post about exposure compensation, a camera will expose the scene to try to get an average of mid-tone grey, also known as middle grey.

Photo #1 (below) was taken with my phone (Sony Xperia Z3 Compact) at the beach at sunset, wtih the phone's camera in full auto mode. As expected, the camera over-exposed the dark sky as it tried to get the average exposre to middle grey. This does not capture the scene as the human eye saw it, and the sunset colours are lost in the background.

photo #1: photo taken with camera in auto mode

By changing to manual mode, and dialling in two stops of negative exposure compensation, I was able to capture photo #2 (below). This is much closer to what the human eye was seeing, and has captured the awesome sunset colours much better than photo #1.

photo #2: photo taken in manual mode, with 2 stops of -ve exposure compensation

By understanding what the camera is doing (attempting to expose for an average of middle grey), and applying some negative exposure compensation, I was quickly and easily able to get a much better photo of the sunset.