Canon PowerShot SD1400IS User Manual page 82

You can use a TV to display the camera screen content while shooting.
Connect the camera to a TV as described in "Viewing Images on a TV"
(p. 115).
Shooting procedures are the same as when using the camera screen.
While you keep the shutter button pressed halfway, the focus and exposure
are locked. You can now recompose and shoot. This is called Focus Lock.
Focus.
Center the subject you want in focus, and
press the shutter button halfway.
Confirm that the AF Frame is green.
Recompose.
....... Keep the shutter button pressed halfway
and recompose the scene.
3 s.oo
Press the shutter button fully.
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