Canon Speedlite 580EX II Instruction Manual page 52

Auto zoom does not work.
The Speedlite is not attached securely to the camera.
Attach the Speedlite's mounting foot securely to the camera. (p.9)
The flash range scale bars blink.
The flash head has been tilted down by 7°.
Change the bounce position. (p.19)
The periphery or bottom of the picture looks dark.
When you set the flash coverage manually, the setting was a higher
number than the lens focal length, resulting in a dark periphery.
Set the flash coverage that is a lower number than the lens focal
length or set it to auto zoom. (p.20)
If only the bottom of the picture looks dark, you were too
close to the subject.
If the subject is closer than 2 m/6.6 ft, tilt the flash head downward
by 7° (bounce flash). (p.19)
The flash exposure is underexposed or overexposed.
There was a highly reflective object (glass window, etc.) in the picture.
Use FE lock. (p.16)
The subject looks very dark or very bright.
Set flash exposure compensation. For a dark subject, set a
decreased flash exposure. And for a bright subject, set an
increased flash exposure. (p.14)
You used high-speed sync.
With high-speed sync, the effective flash range will be shorter. Make
sure the subject is within the effective flash range displayed. (p.17)
The picture is really blurred.
The shooting mode was set to <W>, and the scene was dark.
Use a tripod or set the shooting mode to <V>. (p.12)
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