I have just recently used the metering scale. I assume that if the scale arrow points in the middle, this means that the camera detects that the current exposure settings are the "right" ones.
However, I assume there would be times when you want to go above or below the middle point in the scale. The problem is, I do not know what those situations are. So, what are those situations?
As a side question, what does the -1 and +1 or -2 and +2 mean here?