Nikon D5 - Manual (Page 109)

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87
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Image Recording Options
Choose from image areas of FX (36 Ч 24) 1.0Ч (FX format), DX
(24 Ч 16) 1.5Ч (DX format), 5 : 4 (30 × 24), and 1.2Ч (30 Ч 20)
1.2Ч. See page 385 for information on the number of pictures that
can be stored at different image area settings.
Image Area
DX format (24×16)
image circle
FX format (36×24)
image circle
FX format
1.2×
5 : 4
DX format