Canon MARK II EOS 5D Instruction Manual page 104

D Flash Photography
Using Non-Canon Flash Units
Sync Speed
The camera can synchronize with non-Canon compact flash units at 1/
200 sec. and slower speeds. With large studio flash units, since the
flash duration is longer, set the sync speed within 1/60 sec. to 1/30 sec.
Be sure to test the flash synchronization before shooting.
PC Terminal
Cautions for Live View shooting
When using a non-Canon flash unit for Live View shooting, set the [6
Live View/Movie func. set.] menu's [Silent shoot.] to [Disable]
(p.120). The flash will not fire if it is set to [Mode 1] or [Mode 2].
If the camera is used with a flash unit or flash accessory dedicated to
another camera brand, the camera may not operate properly and
malfunction may result.
Do not connect to the camera's PC terminal any flash unit requiring 250
V or more.
Do not attach a high-voltage flash unit on the camera's hot shoe. It might
not fire.
A flash unit attached to the camera's hot shoe and a flash unit connected to
the PC terminal can both be used at the same time.
104
The camera's PC terminal can be
used with flash units having a sync
cord. The PC terminal is threaded to
prevent inadvertent disconnection.
The camera's PC terminal has no
polarity. You can connect any sync
cord regardless of its polarity.