Nikon D700 - Manual (Page 146)

120
Z
3
Frame a photograph, focus, and shoot.
A Non-CPU Lenses (pg. 372)
If the maximum aperture of the lens has been
specified using the Non-CPU lens data item in
setup menu (pg. 211) when a non-CPU lens is
attached, the current f-number will be displayed
in the viewfinder and control panel, rounded to
the nearest full stop. Otherwise the aperture
displays will show only the number of stops (F,
with maximum aperture displayed as FA) and
the f-number must be read from the lens aperture ring.