The Canon Speedlite 550EX features an AF-assist beam, which links the area AF, Flash Exposure Bracketing, FE lock, E-TTL wireless multi-flash control system and slave unit control. It also incorporates a built-in wireless transmitter, which can control other Speedlite 550EX units set up as slave units. Working in this way, the E-TTL wireless flash operations, which can be controlled, are preflash evaluative flash metering, high speed sync and FE lock.

For E-TTL wireless (multi-flash) autoflash shots, the ST-E2 Speedlite Transmitter mounted on the camera's hot shoe controls one or two Speedlite groups. The system is compatible with E-TTL autoflash on the Speedlite 550EX.

Flash coverage is set automatically from 24mm to 105mm, and a wide-angle panel extends the coverage to 17mm.

• Guide No. (at ISO 100/m): 55
• Bounce: Yes
• Zoom: Yes
• Swivel: Yes
• Type: Dedicated