Canon EOS REBEL T2I Instruction Manual page 31

Preventing Camera Shake*
The camera's mechanical shake caused by the reflex mirror action can
blur images taken with a super telephoto lens or close-up (macro) lens.
In such cases, mirror Iockup is effective.
Mirror Jockup is enabled by selecting the [_ Custom Functions
(C.Fn)] menu's [Mirror Jockup] and setting it to [1: EnabJe] (p.195)o
_ Focus the subject, press the shutter button completely.
_2_ The mirror will swing up.
_ Press the shutter button completely again.
_y,, T he picture is taken and the mirror goes back down.
"_ Shooting Tips
® Using the selfotimer <_)2> with mirror Iockupo
When you press the shutter button completely, the mirror locks up,
then the picture is taken 2 sec. later.
® Remote controJ shooting.
Since you do not touch the camera when the picture is taken, remote
control shooting together with mirror Iockup can further prevent
camera shake. With Remote Controller RC-6 set to a 2-sec. delay,
press the transmit button, the mirror will Iockup and the picture will
be taken 2 sec. later.
_ Do not point the camera toward the sun. The sun's heat can damage [he
camera's internal components.
® [fyou use the self-t_mer and m_rrorIOCKUp In combination with a bulb exposure.
keep pressing the shutter button completely (self-timer delay urne + eu_D
exposure time). If you let go of the shutter button during the self-timer
countdown, there will be a shutter-release souna, put no picture will be taken.
106
Even if <m__i>(Continuous shooting) has been set. single shooun£ wm
lake effect.
If 30 seconds elapse after the mirror has locked up, it will go PaCK oown
au[omatically. Pressing the shutter button eompleteiy again locks up the
mirror again.