Flash: The Basics Small portable flash units have revolutionized 35mm SLR photography, freeing us from the limitations of natural light.  Millions of amateurs own cameras with built in flash, yet flash is one of the least understood tools of photography.  Understanding just the basics of how flash works, will let you do some pretty amazing things with flash. Flash photography requires that you learn and work within the quirky characteristics of flash illumination.  Light from any single camera [...]