- Compatible Cameras: Type A EOS cameras (E- TTL, autoflash); Type B EOS cameras (Manual flash)
- Channels: 4
- Flash Ratio Control: For A:B ratio: 1:8 to 8:1, in half- step increments or 13 steps
- High- Speed Sync (FP flash): Enabled with high-speed sync mode
- Slave Operation Confirmation: With test transmission button.
Slave A fires followed by slave B at 1/64 output. - Flash Exposure Confirmation:
- Before flash fires during FE lock Adequate flash exposure indicated by the flash exposure level icon lit in the viewfinder. Insufficient flash exposure indicated by the flash exposure level icon blinking in the viewfinder.
- After flash fires ST-E2's flash confirmation lamp lights in green for 3 sec.
- Wireless slave SE mode cancellation: Cancels when the test transmission button or FE lock botton is pressed to turn on the slave unit.
- Wireless Transmission: Infrared pulse
- Transmission Range: Indoors: Approx. 12-15 meters/39.4 - 49.2 ft; Outdoors: Approx. 8-10/ 26.2-32.8 ft
- Transmission Coverage: ±40° horizontal and ±30° vertical
- Battery Life: Approx. 1,500 transmissions (At room temperature and with a new set of batteries)
- AF-assist Beam: Compatible with EOS-3's 45-point Area AF and 28mm and longer lens focal lengths
- AF-assist Beam Effective Range: Approx. 0,6 to 10 m/2.0 to 16.5 ft along the periphery (in total darkness).
- SE Feature: While the power switch is set to I or HOLD, the transmission turns off automatically after about 90 sec. of non-use.
- Power Source: 2CR2 lithium (6V) battery x 1
- Dimensions: 62 (W) x 51 (H) x 80 (D) mm/2,4 (W) x 3,1 (D) in
- Weight: 100 g/ 3.5 oz (exluding battery)