Nikon J3 - Manual (Page 223)

203
n
If the lens supports autofocus with manual override, after
focusing using autofocus you can keep the shutter-release
button pressed halfway and rotate the lens focus ring to fine-
tune focus manually. To refocus using autofocus, press the
shutter-release button halfway again.
To zoom in on the display for more
precise focus, press
J (note that this
feature is not available during movie
recording or in slow-motion movie
mode). The display will be zoomed in
to the magnification selected in Step 1
and a navigation window will appear
in a gray frame at the bottom right of
the display.
Navigation window
Use the multi selector to scroll to areas
of the frame not visible in the display.
Press
J to exit zoom.