Canon PowerShot G9 - Manual (Page 249)

Appendix 247
z [Flash Control] will not display when the flash is turned off.
Before making flash settings, turn the flash on.
z When an external flash is mounted, you cannot make built-in
flash settings.
z When adjusting flash exposure compensation with the
camera, set the external flash’s exposure compensation to
[+0].
z If the external flash has been set to stroboscopic flash, the
flash’s set up menu cannot be selected (580EX II only).
z When [Wireless Func.] is set to [On], [Shutter Sync.] cannot
be set to [2nd-curtain]. Even if you set [Shutter Sync.] to
[2nd-curtain] with the camera, it will change to [1st-curtain].
z For continuous shooting, the flash can be in quick flash
mode (pilot lamp lit green). In this case, light emission may
be smaller than with full flash (pilot lamp lit red).
z The focus bracketing mode and the AEB mode cannot be
used for flash photography. If the flash fires, only one image
gets recorded.
z Flashes (especially high-voltage flashes) or flash
accessories made by other manufacturers may override
certain camera functions or cause a camera malfunction.