Roberta Govoni
What is exposure compensation in photography?
In some digital cameras and in every DSLR, with exposure compensation, you can over or underexpose the sensor in third, half, two or three stops.
+1 increases the amount of light by one stop
-1 decreases the amount of light by one stop
It is most effective when used with centre-weighted or spot metering

Tip #1 - It's better to take the photo underexposed. You can bring back details in the shadows, but you can’t get back details in the highlights if they are blown out.
How to: determine the exposure of
Light
cloud and overcast: reduce shutter speed, increase the aperture.
bright and sunny: fast shutter speed, small aperture
Moving Subject: increase shutter speed, unless want blur
Greater depth of field: small aperture
Here a gallery of photos of a lovely family, in Melbourne, where I used the exposure compensation in camera, instead of changing aperture or shutter speed.