User guide

Major Specifications
Camera's Flash Exposure Warnings
Mode
Warning Indication Description
Remarks
Program AE
Minimum aperture
setting blinks.
The subject is too
bright.
Attach a neutral-density
(ND) filter to the lens to
reduce the amount of light
received by the camera
Aperture-priority
AE
Fastest sync speed
blinks.
The background will
be overexposed.
Only the flash exposure
setting for the subject is
correct Setting a smaller
aperture could stop the
shutter speed from blinking.
Shutter speed-
priority AE
Minimum aperture
setting blinks.
The background will
be overexposed.
Only the flash exposure
setting for the subject is
correct.
Maximum aperture
setting blinks.
The background will
be underexposed.
Preconditions for AF-Assist Beam Emission
420EX & EOS Camera Combination
AF-assist by
420EX
AF-assist by the
Camera
EOS 30/ EOS ELAN 7E, EOS-1 V,
EOS 300/REBEL 2000, EOS-3, EOS IX 7/IX Lite,
EOS IX, EOS REBEL G/500N,
EOS ELAN ll/ll E/50/50 E, EOS-1 N, EOS-1 N RS,
EOS REBEL ll/REBEL S 11/1000 N/1000 FN,
EOS ELAN/100, EOS REBEL/REBEL S/1000/1000 F
EOS 700, EOS RT, EOS-1, EOS 630/600, EOS 850,
EOS 750, EOS 620, EOS 650
O
-
EOS 3000/88, EOS 5000/888,
EOS REBEL X/REBEL XS/500, EOS 5/A2/A2E,
EOS 10/1 OS
- O
If the EOS camera has multiple focusing points and focus cannot be achieved with the
420EX’s AF-assist beam or if the 420EX's AF-assist beam is not emitted, focus with the
center focusing point
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