Canon 550EX - Manual (Page 119)

Specifications
Flash-ready indication: (1) Red pilot lamp indicates normal flash ready.
(2) Yellow pilot lamp indicates quick flash ready.
AF-assist beam linkage and range:
Linked to area AF (45 focusing points), effective from approx. 0.6 to 10
meters / 2 to 33 feet at the center and 0.6 to 5 meters / 2 to 16 feet along
the periphery (in total darkness).
Wireless functions
Transmission system:
Configuration:
Wireless switchover: Optical pulse transmission
Camera, master unit, and slave unit(s)
With wireless selector
Wireless selector positions:
OFF, Master, Slave
Channels: 4
[Master unit]
Transmission angle:
Transmission range:
No. of transmissions:
Controllable slaves:
Flash control:
Flash ratio control:
Master flash:
[Slave unit]
Reception angle:
Flash coverage:
Flash-ready indication:
Flash modes:
Horizontal: Approx. 80° / Vertical: Approx. 60° (At B1 zoom setting)
(Manual zooming of flash head also enabled)
Indoors: Approx 12 to 15 meters / 39.3 to 49.2 feet
Outdoors: Approx. 8 to 10 meters / 26.2 to 32.8 feet
Approx. 1500 (without master unit firing)
A, B, C (3 groups)
(1) E-TTL autoflash (with Type-A cameras)
High-speed sync (FP flash) / FE lock / flash exposure compensation /
FEB / flash ratio control
(2) Manual flash (with Type A and B cameras)
(3) Stroboscopic flash (with Type A and B cameras)
A:B = 8:1 to 1:1 or 1:1 to 1:8 (In thirteen 1/2-stop increments)
(For C, flash exposure compensation can be set up to ±3 stops in 1/3 or
1
/
2
-stop increments.)
ON/OFF possible (When ON, automatic set as slave unit A.)
Horizontal: Approx, 80° / Vertical: Approx. 80°
Set automatically to
01 ?Hmm (Manual zooming of flash head also enabled)
AF-assist beam emitter blinks
(1) Controlled automatically by master unit.
(2) Manual flash and stroboscopic flash settable independently from master
unit.
Flash exposure compensation:
Settable individually with each slave unit up to ±3 stops in 1/3- or 1/2-stop
increments
Slave Operation Confirmation:
Enabled with master unit's test firing button
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