Type : Mode - E-TTL II, E-TTL, TTL
Guide Number : 141 ft./43m (at ISO 100); flash head at 105mm zoom setting
Flash Coverage : Fixed condenser lens with inner zoom: (1) Auto Zoom, (2) Manual Zoom, (3) Wide Panel

Zoom positions : 24mm, 28mm, 35mm, 50mm, 70mm, 80mm, 105mm; Indicated by numerals on the LCD's focal length display

Image Size Zoom Control : With cameras compatible with auto zoom, it zooms automatically to match the camera's image size

Number of Flashes : Approx. 200 to 1,400, with AA-size Alkaline Batteries manufactured within the last three months or AA-size Ni-MH fully charged batteries.

Recycling Time : Approx. 0.1 to 3.7 seconds (AA-size Alkaline Batteries)/0.1 to 2 seconds (AA-size Ni-MH batteries)

Flash Range : At ISO 100, with EF 50mm f/1.4
For normal flash : Approx. 2.3-79.7 ft./0.7-24.3m
For high sync speed (EF flash) : Approx. 2.3-39.4 ft./0.7-12m
AF Assist Beam : Built-in; covers all focus points in EOS cameras up to 9 AF points

Effective range -
At center : Approx. 2.3-32.8 ft./0.7-10m
Periphery : Approx. 2.3-16.4 ft./0.7-5m (in total darkness)

Custom Functions : Six user-selectable Custom Functions built-in; set on Speedlite's LCD panel