This is a successor to the Speedlite 380EX. It had an autozoom tilt-and-swivel head, maximum guide number of 42 (with 105mm lens, ISO 100m) and E-TTL flash metering. E-TTL flash is only possible with Type A cameras. TTL metering is used with other models. Features include: AF-assist
This is linked to the seven focusing points. It emits a cross-type pattern with vertical an horizontal stripes. The effective range is up to a maximum of about 7 meters. Wireless slave unit setting
When a Speedlite 550EX, Speedlite Transmitter ST-E2 or Macro Ring Lite MR-14EX is used with a Type-A camera (enabling E-TTL flash metering), Speedlite 420EX can be used as a slave unit. Exposure will be controlled by the master unit. An unlimited number of 420EX units can be used and controlled by the master unit. Modelling flash
The 420EX will fire for one second at 70Hz to show the effect of the flash. This facility is only available with the EOS 1V, EOS 3 and EOS 30. The speedlite 420EX runs from four AA-size batteries (alkaline, Ni-CD, Ni-MH or lithium). The size is about 10% less tan the Speedlite 380EX. EOS magazine, December 2000, page 13 Type: Direct-contact, shoe-mount flash with E-TTL/TTl autoflash. (AF-assist beam, autozoom head, bounce flash and wireless slave setting provided.)
Compatible cameras: Type-A EOS cameras (E-TTL autoflash)
Type-B cameras (TTL autoflash)
Flash duration: 1.2ms or less with normal flash
Flash coverage: autozoom head is positioned automatically to suit the lens focal length (24mm, 28mm, 35mm, 50mm, 70mm and 105mm)
Flash modes:
• normal sync
• high-speed sync (FP flash)
• test firing
• modelling flash (at 70 Hz for 1 sec.)
Exposure control modes:
• E-TTl autoflash (with Type-A cameras and preflash evaluative metering)
• FE lock (with Type-A cameras and preflash evaluative metering)
• TTL autoflash (with Type-B cameras and off-the-film flash metering)
Flash exposure compensation:
• automatic flash output reduction for fill flash
• enabled with cameras having a flash exposure compensation feature
Flash range:
• with normal sync: 0.7 - 24.2 meters
• with high-speed sync: 0.7 - 12.7 meters (at 1/180 sec.)
Flash-ready indication: red pilot lamp
Flash exposure confirmation: yellow-green lamp
AF-assist beam range: covers 1, 3, 5, or 7 focusing points (covers only a part of the 45-point area AF)
Range at centre: approx. 0.7 - 7m
Range at periphery: approx. 0.7 - 5m (in total darkness)
Wireless slave setting: slave setting: wireless selector set to SLAVE
Channels: 4
Slave group ID: A, B, C
Reception angle: approx. +/-40° horizontal, +/-30° vertical
Flash coverage: set to 24mm automatically
Flash-ready indicator: AF-assist beam emitter blinks
Exposure control: automatic with the master unit (for E-TTL autoflash)
Test flash: enabled with master unit’s test firing button
SE mode: power turns off automatically after 90 sec. of non-use
Power turns on with test firing button
Power source:
• four size-AA alkaline batteries
• four size-AA Ni-Cd batteries
• four size-AA nickel-hydride batteries
• four size-AA lithium batteries
Dimensions (mm): 71.5 (W) x 123 (H) x 99.4 (D) mm
Weight: 300g (excluding batteries)
Guide No.
[normal sync] (at ISO 100 in meters) | 
