Canon has released a line of new hot shoe and battery accessories designed for its recently upgraded pro and midrange cameras. The Speedlite 600EX-RT, Canon's first flash unit with built-in wireless radio connectivity, replaces the Speedlite 580EX II. It can be used with Canon's new ST-E3-RT radio-frequency wireless Speedlite transmitter and can be positioned up to 30 meters away and has a bounce-and-swivel head with zoom correction...