Canon EOS Rebel Ti Instructions Manual page 34

Focusing Off-Center Subiects
lf you want to focus an off-center subject not covered by any of the AF
points, use focus lock as described below.
-$ Select the desired AF point.
s (-+page 32)
p Focus the subiect.
&\ . Aim the AF point on the subject, then
press the shutter button halfwaY.
ffi Keep pressing the shutter button
d halfway and recompose the
picture as desired.
$fu
rare the picture.
Focus lock also works in the Basic Zone modes (exceptcKt). Just start
from step 2 above.
33