Pentax ZOOM 105-R Operating Manual page 20

If you shoot without positioning the autofocus frame (^ ^)
on the main subject of the picture as shown above, only
the background will be in focus. When the mam subject of
your picture is off the aulofocus frame in the center of the
viewfinder, use the focus-lock technique.
I on the mam
D
First position the autofocus frame i
subject
□ As you press the shutter release button halfway the
green lamp (
AF
) glows, and focus and exposure are
temporarily locked