EXPOSURE COMPENSATION: MAKING IT EASY TO UNDERSTAND
Exposure compensation is usually a tricky one for new photographers to use. Hopefully, this short walk-through will make it easier. The first thing to understand about exposure compensation is that it only applies to certain shooting modes. It only applies to programmed, shutter priority, or aperture priority modes.
When adjusting the exposure compensation, you can go left or right of the dial. There will be a plus, or negative, sign to let you know how you are exposing the photo. Depending on your settings, you can adjust your exposure compensation in 1/3 or 1/2 stops. To adjust your exposure a full stop, you will need to select the nearest whole number. On my Nikon I can adjust up to five full stops.
The image above is a collage of photos I took in my yard to demonstrate how exposure compensation works. To set this up, I selected shutter priority mode and chose a shutter speed of 1/30th of a second for each shot. The middle frame, 0, represents even exposure per the meter in my camera. As I added exposure compensation (images going to the left) you can see the result is brighter without me having to change my shutter speed. If my camera set up to adjust using 1/2 stops, the compensation above would have looked like "+1, +.5, 0, -.5, -1." As you can see, exposure compensation can alter the photo without you changing your shutter speed, or aperture if you are in aperture priority mode.
Someone might still be looking for a more practical example for using this setting. If you are photographing wildlife at dusk, it can be challenging to use a shutter speed that is fast enough to prevent movement. In the past, I would have tried to use a slower speed to allow more light, or bumped up my ISO. Instead, I can use positive compensation and keep my fast shutter speed. Using this first, versus higher ISO, can help keep noise out of my image.
Hope this helps anyone that is learning. If you have any questions, feel free to email me.