Canon SPEEDLITE EL-1 Advanced User's Manual page 161

Positioning and Operation Range
Automatic Flash Photography with 1 Flash Receiver ( )
(1) Indoors
(2) Outdoors
(3)
(4) About 80°
(5) Transmission range
(6) About 8 m / 26.2 ft.
(7) About 12 m / 39.4 ft.
(8) About 10 m / 32.8 ft.
(9) About 15 m / 49.2 ft.
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