The flash unit supports both TTL and E-TTL/E-TTL II automated flash metering (when used with compatible cameras). Manual control over flash output is supported by built-in controls, with a power range of 1 to 1/64.
Guide number (power output).
The unit has a zooming flash head which moves internally to adjust for the lens focal length. Control over the zoom position is both manual and automatic. The zoom range is from 24-105 mm, with zoom detents (stops) at 24, 28, 35, 50, 70, 80 and 105mm.
The flash zoom function is capable of taking the camera’s image sensor size into account if the camera is also capable of transmitting that data to the flash unit. In such a case the flash can adjust its zoom to match a reduced (less than 35mm film frame) sensor size, and so wastes a minimum of light around the edges.
The unit’s guide number (provided in metres, not feet, for ISO 100) varies depending on the zoom head settings.
· At 14mm (with the flip-down diffuser in place) the guide number is 11.
· At 24mm the guide number is 25.
· At 28mm the guide number is 27.
· At 35mm the guide number is 31.
· At 50mm the guide number is 34.
· At 70mm the guide number is 37.
· At 80mm the guide number is 40.
· At 105mm the guide number is 43.
The flash unit has a built-in red autofocus assist light, with a range of 0.8-7 metres. The AF assist covers all focus points of all current and past EOS cameras, whether they have 1, 3, 5, 7, 9 or 45 focus points.
Flash head movement.
The flash head can both tilt and swivel with a handy single catch to release the tilt and swivel motions (most tilt/swivel flash units have two catches). The head has a flip-out diffuser panel which can diffuse light up to a focal length of 14mm.
Type A functions.
Since this flash unit supports E-TTL it also supports certain features when used with compatible type A cameras.
· Flash exposure lock (FEL) with compatible cameras.
· FP mode (high speed sync) flash on automatic with FP mode controls.
· Wireless E-TTL – slave capabilities only.
· Uses a simple slider switch, not a fiddly menu option, to control the master/slave mode.
· Modelling light support when used with compatible cameras.
· Supports automatic white balance compensation with compatible cameras.
· Flash exposure confirmation indicator on back panel.
· Support for second-curtain synchronization if the camera has the appropriate custom function.
· Support for second-curtain synchronization via back panel control.
· Flash exposure compensation (FEC) controls on back panel .
· Back panel LCD (liquid crystal display).
· Backlight illumination for LCD.
· Flash has custom functions, adjustable by back-panel controls (see full list of functions below).
· Save Energy (SE) function, with a timeout value of 90 seconds.
· Powered by four standard AA cells – alkaline, NiCad, NiMH.
· Also compatible with lithium AA cells.
· Plastic flash foot.
· Flash foot has a locking hotshoe.
· Weight: 300g.
· Size: 72mm W x 122mm H x 101mm D.
1) Auto power off (on/off)
2) Power-off in slave mode (60 min, 10 min)
3) Auto-zoom for subframe digital cameras (on/off)
4) AF-assist beam (on/off)
5) Modelling flash (on/off)
6) LCD when shutter release pressed halfway (maximum range/aperture)