Cropping allows for crops, pans, and zooms over the duration of the selected item on the Primary Timeline. Upon opening the tool, Cropping Thumbnails for Starting Position and End Position will be displayed. Tap either thumbnail to select it, and then Spread to zoom in or Pinch to zoom out on the Cropping Preview. Tap = to make the Starting Position and End Position identical.
If the Starting Position and End Position are set to be identical, a still crop is produced. If they’re different, then the Cropping tool linearly and dynamically interpolates the rate of pan and zoom over the entire length in time of the selected item, creating Ken Burns style pans and zooms.