In this tutorials it shows you how to create a camera flashes in After Effects. You see them on the TV when there is a celebrity and photographers snapping away!
Import file in to a new composition
Make a new black solid and add a lens flare effect
Change the lens flare to 105mm prime and animate the flare brightness and change blend
Duplicate layer as many times as you need and offset time
Use video instead of an image
Add a flash noise