Canon EOS 60D Instruction Manual page 286

Troubleshooting Guide
When I use the <f> mode with flash, the shutter speed
becomes slow.
If you shoot at night when the background is dark, the shutter speed
becomes slow automatically (slow-sync shooting) so that both the
subject and background are properly exposed. If you do not want a
slow shutter speed to be set, set [8C.Fn I -7: Flash sync. speed in
Av mode] to 1 or 2 (p.253).
The built-in flash does not fire.
If you shoot continuously with the built-in flash at short intervals, the
flash might stop operating to protect the flash unit.
Flash exposure compensation cannot be set.
If flash exposure compensation has already been set with the
Speedlite, flash exposure compensation cannot be set with the
camera. When the Speedlite's flash exposure compensation is
canceled (set to 0), flash exposure compensation can be set with the
camera.
High-speed sync cannot be set in the Av mode.
Set [8C.Fn I -7: Flash sync. speed in Av mode] to [0: Auto]
(p.253).
The external flash does not fire.
If you use a non-Canon flash with Live View shooting, set the [z
Silent shoot.] menu option to [Disable] (p.159).
The camera makes a noise when it is shaken.
The built-in flash's pop-up mechanism moves slightly. This is normal.
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