FujiFilm FinePix XP120 - Manual (Page 56)

38 More on Photography
Focus Lock
To compose photographs with off-center subjects:
1
Focus: Position the subject in the focus frame (U)
and press the shutter button halfway to lock focus
and exposure. Focus and exposure will remain locked
while the shutter button is pressed halfway (AF/AE
lock).
2
Recompose: Keep the button pressed halfway.
3
Shoot: Press the button all the way down.