The maxim "every picture tells a story" usually comes under challenge whenever an amateur videographer works without understanding the basic language of the moving picture medium. In this era of YouTube, such a lack of knowledge is more common than not.
Just as an understanding of grammar is an ingredient in good writing, there are conventions that audiences have come to expect when watching video or film. Rules, of course, are made to be broken by artists. Most of today's camcorder users, however, are not artists. Those who ignore the tried-and-true conventions of the motion picture process without understanding why are usually doomed to failure.
Every video should tell a story. How the videographer selects the individual images and pieces them together in an edited sequence determines whether the story is effectively told or leaves the audience confused.
A key consideration in creating a sequence of shots is to maintain clear screen direction for the viewer. That is, to keep everything--people and objects--facing the same direction as the camera switches shots.
Though this may sound simple and obvious, it is a common problem that can cause the audience to become disoriented when the camera position is changed.
All of us have seen reverse cuts when a person moving one way across the screen suddenly reverses direction; or when two people, facing each other, are having a conversation and suddenly one appears to be talking from behind the other. In both cases, the camera operator has "crossed the line."
The so-called "line" represents an imaginary linear reference point drawn through a scene over which the camera may not cross without shaking the audience's sense of screen geography. The line can be referenced to movement, eye contact between subjects or any other area of interest in the scene.
As long as the camera stays on one side of the line, it can move freely from shot to shot, and screen direction will be maintained. Though in theory this sounds like a simple rule to follow, in the real world of production, there are times when crossing the line is necessary. There are several ways to do so without confusing the audience. These techniques are essential to the videomaker's craft.
One way to cross the line is to let the audience see the subject change direction on screen. For example, a motorcycle that moves toward the right of the screen, then turns and moves toward the viewer and then turns away and moves to the left clearly alerts the audience to the changes in screen direction. In this case, the camera never moved and the line simply changed with the on-screen action.
Another way to shoot this same scene would be to have the camera move on a track across the line as it follows the movements of the motorcycle. Again, the audience sees the motorcycle reverse direction and keeps its geographic footing on the screen.
A frequently used method for crossing the line is to place the camera exactly on-the-line for a transition shot. Examples of this can be found in one the greatest chase scenes ever filmed.
The chase in The French Connection not only demonstrates how to cross the line by intercutting an on-the-line transition shot, but how the use of artful composition and rapidly sequenced camera angles can build suspense.
In constructing this scene, director William Friedkin used knowledge that artists have known about picture composition for centuries: Objects placed in the right side of a rectangle communicate an exaggerated sense of power, while objects placed on the left create uneasiness and tension.Freidkin also knew that scientists have discovered that when we view a surface--like a television or movie screen--our eyes constantly move in a pattern around the screen. Our brain resolves that movement into a steady image. The director used this natural eye movement and left side discomfort along with some fancy cross-the-line footwork to create tension in this classic chase sequence.
Gene Hackman, as Popeye Doyle, pursues a villain on a train. The scene begins with emphasis on the right side of the screen. Then the action moves to the left. Then a neutral shot—a shot made directly on-the-line—is introduced. It is Hackman behind the wheel of his car.This shot allows a reverse of screen direction. Then the scene gradually gets more tense, the action moving sharply to the left and the camera angle frequently crossing back and forth across the line. The human eye and the objects on the screen collide, inducing stress in the viewer.
But as screen direction flip-flops back and forth, the audience is never confused or disoriented. The sense of time and place are always secure. This scene is a study in how crossing the line can transcend into an art form.
The basic rules of crossing the line should be mastered by every video camera operator. Failure to do so highlights one's amateur status.