Sense of motion describes the readability of anyone or anything that moves through space. Like a person walking through a room, a car driving along a street, a bird flying through the sky. Basically anything that travels from A to B. In order to get a clear read through lighting lights can be for example animated, placed strategically to get a sense of going in and out of shadows or fake reflections can be projected to name just a few.
The examples below achieve a good read of the motion through animating lights, adding moving reflections or letting the actor walk in and out of shadows. To play the videos simply click on them.
Blade Runner, Cinematographer: Jordan Cronenweth
Sense of motion through flickering lights
Sicario, Cinematographer: Roger Deakins
Lights animated to simulate a flying airplane. Similar lighting technique has been used in ‘Batman Begins’ during a dialog scene with Bruce Wayne and Butler Alfred.
The Big Combo, Cinematographer: John Alton
Actors running in and out of light and shadow.
Chinatown, Cinematographer: John A. Alonzo
Short clip from a 1 minute long sequence in which the lighting doesn’t change. No sense of motion can be read through the lighting
Sense of motion in CG:
Getting a good sense of motion in CG can, depending on how the animation is done, be really hard. What might look slow in screen space might actually travel really fast in world space and vise versa. It might not be always easy to justify this kind of lighting effect either but anything you will do in this regard to avoid static lighting will help to sell the sense of movement. Its crucial to match the speed of the animation to emphasis how fast or slow something is moving. Reflections on a car window that seem to pass by with 1000 km/h are as unbelievable as an air plane flying with 5km/h.