Nikon D5 User Manual page 94

A
Image Area
At frame sizes of 1920 × 1080 and 1280 × 720, you can choose an image
area using the Image area > Choose image area option in the movie
shooting menu. Select FX to shoot movies in what is referred to as "FX-
based movie format", DX to shoot in "DX-based movie format". The
differences between the two are illustrated below.
FX (36×24) DX (24×16)
The sizes of the areas recorded are approximately 35.9 × 20.2 mm (FX-
based movie format) and 23.5 × 13.2 mm (DX-based movie format).
Movies shot with a DX-format lens and On is selected for Image area >
y
Auto DX crop (0 88) in the movie shooting menu are recorded in DX-
based movie format.
At frame sizes of 3840 × 2160 and 1920 × 1080 crop, image-area
selection is not available and image area remains the same regardless of
the type of lens used.
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