Nikon D6 Reference Manual page 1098

4 Can be used only if the lens focal length and maximum aperture are
specified using the [Non-CPU lens data] item in the setup menu.
Some lenses may, however, fail to produce the desired results even if
the focal length and maximum aperture are supplied. Use [Spot
metering] or [Center-weighted metering] if the desired results are
not achieved.
5 For improved precision, specify the lens focal length and maximum
aperture using the [Non-CPU lens data] item in the setup menu.
6 Can be used in mode M at shutter speeds one step or more slower
than the flash sync speed.
7 Use stop-down metering. In mode A, stop aperture down using the
controls on the lens and lock exposure before shifting the lens. In
mode M, stop aperture down using the controls on the lens and
meter exposure before shifting the lens.
8 Exposure compensation required with AI 28–85mm f/3.5–4.5, AI 35–
105mm f/3.5–4.5, AI 35–135mm f/3.5–4.5, or AF-S 80–200mm
f/2.8D lenses.
9 Requires a PK-12 or PK-13 auto extension ring. A PB-6D may be
required depending on camera orientation.
10 Can be used with stop-down metering; in mode A, stop aperture
down using the controls on the bellows attachment and meter
exposure before taking photographs.
•
Lines may appear at high ISO sensitivities when aperture is adjusted
during movie recording or live view photography.
1046 Compatible F Mount Lenses