This is Canon's top of the line flash unit. The list of features is extensive for this camers:* Dedicated to Canon cameras. * -7 to 90 degree bounce. * -90 to 180 degree swivel. * E-TTL and TTL metering. * auto-zoom head. * high speed shutter sync. * rear-curtain sync. * flash exposure compensation. * flash bracketing. * strobe flash. * Manual-flash mode. * Back-lit LCD screen.
The most impressive part of this flash is the ability to perform E-TTL sync among multiple flash units. This allows you to locate various flash units around the subject and trigger them symultaneously. The flash output is adjusted based on the E-TTL and a flash ratio that is set up between the flash units.
The flash unit also includes a distance scale that will read the film speed and aperature from the camera to let you know the range the flash can be used for. Fast film and a wide aperature will often cause the effective range to go off the end of the scale (18 m).
This flash is not for everyone. If you prefer to point and shoot, then this flash is probably more than you'll need. However, if you prefer to think about how the flash should be used or take the flash out of automatic mode then this flash is what you should be looking at.
If you can do without the high speed sync and remote operation, then the Canon 540 EZ may also be worth looking at.
