Canon 1D X - Manual (Page 187)

187
Although using the self-timer or Remote Switch can prevent camera
shake, using mirror lockup to prevent camera vibrations (mirror shock)
can also help when you use a super telephoto lens or shoot close ups
(macro photography).
1
Set [Mirror lockup].
Under the [z3] tab, select [Mirror
lockup], then press <0>.
Select [Enable] or [Enable: Mirror
down w/s], then press <0>.
2
Focus the subject, then press the
shutter button completely.
X The mirror will swing up, and the
<2> icon will blink on the top LCD
panel.
3
Press the shutter button
completely again.
X The picture will be taken.
With [Enable] set, the mirror will go
back down when the shooting ends.
If [Enable: Mirror down w/s] is
set, the mirror lockup will be
maintained even after shooting. To
cancel the mirror lockup, press <0>.
2 Mirror Lockup
COP
Y