Finds motion far smaller than a pixel by watching how brightness at each edge rises and falls over time, then
dividing by the edge's steepness to recover displacement.
Put the camera on something solid. Hand shake swamps everything.
Set the band around the frequency you're hunting. The top is limited to half the frame rate, and faster vibration aliases down into it.
Click anywhere to probe a point: waveform, spectrum and peak frequency.
Lock focus and exposure under Advanced if the picture "breathes".