Canon EOS-1D C EOS 1D X Instruction Manual - Page 381

Troubleshooting Guide When I use the 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. To prevent a slow shutter speed, under [z3: External Speedlite control], set [Flash sync. speed in Av mode] to [1/250-1/60 sec. auto] or [1/250 sec. (fixed)] (p.198). The flash does not fire. Make sure the flash (or PC sync cord) is securely attached to the camera. If you use a non-Canon flash unit with Live View shooting, set [z4: Silent LV shoot.] to [Disable] (p.212). The flash always fires at full output. If you use a flash unit other than an EX-series Speedlite, the flash will always be fired at full output (p.195). When the [Flash metering mode] flash Custom Function is set to [TTL] (autoflash), the flash will always be fired at full output (p.202). 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 mode. Under [z3: External Speedlite control], set [Flash sync. speed in Av mode] to [Auto] (p.198). 381