Off-camera flash is one of the most liberating aspects of flash technology. The idea is to get your camera to capture light that is controlled by you. You set up the flash so you can design how viewer sees your shot. In recent years flash units attached to DSLRs have become very sophisticated. This latest release from Canon has a range of high quality control features and in-built radio technology.
Syl Arena is a well known author in the field of flash technologies. In this article he reviews the latest offering from Canon. It is a rounded and informed view.