Image Area: Choosing a Movie Crop
At frame sizes of 1920 × 1080 and 1280 × 720, you can choose an image area using the  > [ ] option in the movie shooting menu. Select [ ] to shoot movies in what is referred to as “FX-based movie format”, [ ] to shoot in “DX-based movie format”. The differences between the two are illustrated below.
The sizes of the areas recorded in FX- and DX-based movie formats differ. The differences are shown below.
FX-based movie format
Approx. 35.9 × 20.2 mm
DX-based movie format
Approx. 23.5 × 13.2 mm
Movies shot with a DX-format lens and  selected for [ ] > [ ] in the movie shooting menu are recorded in DX-based movie format.
Image-area selection is not available at frame sizes of 3840 × 2160 and “1920 × 1080 crop”. Image area does not change when a DX lens is attached.
Enabling electronic vibration reduction by selecting  for [ ] in the movie shooting menu reduces the size of the crop, slightly increasing the apparent focal length.