It needs using single autofocus for the lens.
Enable or disable the AF assist Beam Emitter
function through the camera menu custom function
(P.24) or speedlite transmitter custom function (P.
25)(C.Fn8).
AF Assist Beam Emitter
When using AF under low-light,
the built-in AF-assist beam emitter
of the speedlite transmitter will
be emitted automatically to make
it easier to autofocus.
29
Reference
Firmware Update
1.Log in the YONGNUO official website (www.hkyongnuo.com)
to download the firmware update software and the latest
firmware.
2.Power off, use USB-MINIB cable connect to PC.
3.Press the <MODE> button and set the power switch to <ON>,
the screen will enter into firmware upgrade interface.
4.Complete the firmware upgrade operation according to the
prompt of software.