Imagine this; You are photographing some people against a window, or another bright background on auto mode, and your camera is adjusting just fine, but you find that the people are a little under- exposed (exposure). You are confused, and perplexed, and have no idea what is going on. Ever been in this situation before?
Let me enlighten you. Your camera is exposing for the highights of the shot (ie. the window) and the main subject is therefore too dark. But, do not despair, for help is at hand. All you need to do is leave auto mode behind. You can learn more about the modes here.
Bring your camera’s pop-up flash up, then select the flash mode to fill-in flash. When you take a picture the background will remain correctly exposed, but the subject will be brightened by the extra burst of light.
The picture above shows a cat. He has been lit up by flash, but his surroundings are illuminated by sun (from behind).
This is a useful technique, which can only be accesed in manual and semi auto modes, so the key is LEAVE AUTO BEHIND!!!!!!