The Speedlite 320EX features, in addition to the traditional flash head, a front-facing LED light that can be used to illuminate subjects in dim lighting conditions. It is well-suited for video or other situations where constant light is required or as a versatile modeling light to be used in combination with the flash. A horizontal and vertical bounce head design aids in greater control over the direction of the flash output and, when used in conjunction with EOS DSLRs with a master function, a built-in slave function allows the flash to be triggered wirelessly. The flash has a selectable wide and tele head positions and provides a guide number of 105' at ISO 100 at the tele position or 78.7' at ISO 100 at the wide position. It supports Canon's E-TTL II flash metering system and can cover EF lenses with focal lengths as wide as 24mm with the wide position.