Canon Speedlite 550EX TTL Shoe Mount Flash

Speedlite 550EX is the main component of a flash system designed together with the EOS-3 SLR camera. It provides full compatibility with the area AF technology employed by the EOS-3 and refined E-TTL autoflash for improved performance. Other main features include a maximum Guide Number of 180 (ISO 100, ft.), an AF-assist beam which links to the EOS-3's 45-point area AF, FP Flash (high speed sync), FE lock (a flash version of AE lock), and FEB (Flash Exposure Bracketing). The Speedlite 550EX also incorporates a built-in wireless transmitter, which can control other Speedlite 550EX units set up as slave units. Flash coverage is set automatically from 24mm to 105mm, and a wide-angle panel extends the coverage to 17mm. The Speedlite runs on 4 AA-size batteries, and can also be used with optional external power supplies such as Compact Battery Pack E and Transistor Pack E. Recycling times are faster than those experienced with the Speedlite 540EZ. Speedlite 550EX is compatible with all EOS models.

Features
High-output shoe-mount flash for EOS System (Maximum GN 55/180, ISO 100 m/ ft.).
Autozoom coverage from 24-105mm with 17mm wide panel built-in.
Compatible with all EOS cameras, but has special features when used with EOS-3.
Supports Wireless Flash with EOS-3 and Speedlite Transmitter ST-E2.
Supports E-TTL, FEL and FP flash (High-Speed Sync) with selected EOS cameras. Other useful features include flash exposure compensation, flash exposure confirmation, flash exposure bracketing, second-curtain sync, variable-power manual flash, stroboscopic flash and more.

 
Specifications
Type Direct- sync, shoe-mount flash with E-TTL/TTL autoflash control and wireless transmission/reception (E-TTL preflash, AF-assist beam, auto zoom, and bounce flash).
Guide Number 138' (42 m) at 50mm
180' (55 m) at 105mm
Zoom Range Auto zoom head covers 24mm, 28mm, 35mm, 50mm, 70mm, 80mm, and 105mm lens focal lengths automatically.

Manual zoom: Enabled with zoom button.

Wide panel: When the built-in wide panel covers the flash head, flash coverage is extended for 17mm lens local length.
Bounce Capability Up Angle: 0° - 90°Click Stops: 0°, 60°, 75°, 90°
Down Angle: 0° - 7°Click Stops: 0°, 7°
Left Angle: 0° - 180°Click Stops: 0°, 60°, 75°, 90°, 120°, 150°, 180°
Right Angle: 0° - 90°Click Stops: 0°, 60°, 75°, 90°
Swivel Capability Yes
Auto Settings Normal flash
Quick flash
High-speed sync (FP flash)
Stroboscopic flash: 41 flash frequency settings, 31 firing settings
Preflash: Obtains exposure reading for E-TTL autoflash control
Test flash: With test firing button
Modeling flash: Fired with the EOS-3's depth-of-field preview button
Angle of Coverage 84° (24mm in 35mm format) to 23.3° (105mm)
103° (17mm) with included wideangle adapter
Recycle Time Internal Only:
4 x AA Alkaline Quick Flash: 0.1 - 4 Norm. Flash: 0.1 - 8
4 x AA Ni-Cd Quick 0.1 - 2.5 Norm. 0.1 - 5
Transistor Pack E:
Ni-Cd Pack TP Quick 0.1 - 1.5 Norm. 0.1 - 3
6 x C Alkaline Quick 0.1 - 2 Norm. 0.1 - 5
Compact Battery Pack CP-E2:
6 x AA Alkaline Quick: 0.1 - 1.5 Norm. 0.1 - 5
6 x AA Ni-Cd Quick: 0.1 - 1 Norm. 0.1 - 2
Power Source Internal Only:
4 x AA Alkaline
4 x AA Ni-Cd

Transistor Pack E:
Ni-Cd Pack TP
6 x C Alkaline

Compact Battery Pack CP-E2:
6 x AA Alkaline
6 x AA Ni-Cd
Dimensions (W x H x D) 3.1 (W) x 5.4 (H) x 4.4 (D) in.
Weight 14.2 oz
Notes & Special Features Flash duration: 1.2 ms or less. For quick flash: 2.3 ms or shorter.
Flash metering system:
E-TTL autoflash with instant metering using a preflash (with Type-A cameras).
E-TTL autoflash with instant partial metering using a preflash (with Type-A cameras).
E-TTL autoflash with instant spot metering using a preflash (with Type-A cameras).
TTL off-the-film auto flash metering (with Type-B cameras).
Notes & Special Features Flash exposure compensation adjustable manually with the Speedlite up to ±3 stops in 1/3- or 1/2- stop increments.
Flash exposure compensation adjustable manually up to ±3 stops in 1/3- or 1/2- stop increments with cameras equipped with flash exposure compensation function.
Flash Exposure Bracketing: Set with the Speedlite up to +/- 3 stops in 1/3-stop or 1/2-stop increments.
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: Optical pulse transmission
Configuration: Camera, master unit, and slave units
Channels: 4 (Master unit)
Transmission angle: Horizontal: Approx. 80° / Vertical: Approx. 60° (@ M 24 mm zoom setting) (Manual zooming of flash head also enabled)
Range: Indoors: Approx. 12 to 15 meters / 39.3 to 49.2 feet Outdoors: Approx. 8 to 10 meters / 26.2 to 32.8 feet
No. of transmissions: Approx. 1500 (without master unit firing)
Controllable slaves: A, B, C (3 groups)