5) All About the EV Scale
The EV scale is centered at zero and extends 2 or 3 stops in both + and – directions, graduated in 1/3rd of a stop intervals.
If you go up on the + side, you are letting more light in, so increasing the exposure. If you go up on the 1 side, you are giving the picture a shorter exposure, which lets less light in.
The EV scale uses the same principles as f-numbers and shutter speeds.
Each full stop in the “+” direction will double the amount of light allowed to fall on the sensor, so making the picture lighter. Every full stop in the “-“ direction will half the amount of light allowed to fall on the sensor, so making the picture darker.