Nikon D3S - Manual (Page 106)

80
d
A
Image Area
The selected option is shown in the information
display.
A
DX Lenses
DX lenses are designed for use with DX format cameras and have a
smaller picture angle than lenses for 35mm format cameras. If Auto DX
crop is off and an option other than DX (24×16) (DX format) is selected
for Image area when a DX lens is attached, the edges of the image may
be eclipsed. This may not be apparent in the viewfinder, but when the
images are played back you may notice a drop in resolution or that the
edges of the picture are blacked out.
A
The Viewfinder Display
The 1.2 ×, DX format, and 5 : 4 crops are shown below.
1.2× DX format 5 : 4