How Steadicams Work

When a person walks or runs, each footstep sends a sizable jolt through the body. For the most part, you don't register these shocks visually, because the brain automatically adjusts the information coming from the eyes; it smooths out the disorienting motion when forming the visual image that the conscious mind is actually aware of.

Some cameras have a built-in adjustment mechanism to compensate for shaking motion, but it doesn't come close to the natural stabilization system in the human brain. The camera will still record a lot of the motion from the camera operator's steps.

Even when an operator is standing still, the camera may pick up a lot of jarring motion. It's so easy to pivot the camera that even a light push in any direction can translate to a considerable jump in the film or video image.

Don't get us wrong. The jolts and shakes of hand-held footage work well for certain scenes -- an unsettling chase in a horror movie (think "Evil Dead") or a bare-bones documentary, and some directors intentionally employ shaky cam, as "The Blair Witch Project" and "Cloverfield" did. But for the most part, filmmakers have shied away from hand-held cinematography. When a scene called for the camera to move, the crew attached it to a dolly, a wheeled platform that rides on a track or smooth floor. Dollies work great for a wide range of shots, but they have certain limitations. You can't use them on stairs, for example, and they are hard to navigate around obstacles. It is also extremely difficult to set them up on rough terrain.

In the early 1970s, a commercial director and producer named Garrett Brown began working on alternative stabilizing systems to get around these limitations. Brown wanted to build a highly portable device that would isolate the camera from the operator, as well as improve the camera's balance, to minimize shakes and shocks.

In 1973, Brown realized his goals with a revolutionary but remarkably simple machine. "Brown's Stabilizer," later renamed Steadicam. Larger models steady a camera using only three major elements:

In the diagram, you can see how these elements come together. The camera, along with a battery and a monitor, are positioned on the sled. The sled is attached to the articulated arm, which is attached to the vest. The arm and vest configuration works to isolate the camera from the body of the cameraman. The sled's job is to provide optimum balance for the camera.

In the next few sections, we'll look at these elements to see how they virtually eliminate the shocks and jolts of hand-held camera operation.

The Steadicam's articulated arm is a lot like a spring-loaded, swing-arm lamp. It consists of two arm segments, connected with a pivoting hinge. Each arm segment is a sort of parallelogram: It's made up of two metal bars, fastened to two metal end blocks. Just as with any parallelogram, the metal bars will remain parallel with each other (or nearly parallel) no matter how the arm is positioned. Since the end blocks are secured to the ends of the parallel bars, they'll remain in the same position as the arm swings up and down (as you can see in the diagram).

If you were to attach a light to one of the end blocks in this design, as in a swing-arm desk lamp, the light would continue to shine in the same direction as you moved the arm up and down. In the same way, a camera attached to one of the end pieces keeps pointing in roughly the same direction. But in order to keep the camera sled absolutely level, the arm grips it with a free-moving gimbal. The sled's own weight distribution keeps the camera balanced (as we'll see later).

In this setup, the weight of the camera sled constantly pulls the arm downward -- it works to bring the parallel metal bars together so that the front block (A and B) of each arm segment is lower than the rear block (C and D).

To counteract this downward force, the parallel metal bars in each arm are connected with a spring system. The spring system works to close the parallelograms the opposite way -- so that the front blocks are higher than the rear blocks. The system is precisely calibrated to exactly match the downward force of the sled's weight. In this way, the arm and the camera sled will stay in the same position until the cameraman shifts the camera up and down.

In the original Steadicam design, the bars were connected directly with springs. In the modern Steadicam, the arrangement is a little more elaborate, but it serves the same function. You can see how this system works in the illustration.

The lower bar in each arm segment is actually a hollow cylinder, with a large coiled spring inside. The spring is attached to a pulley, which is connected to a drum by a pair of metal cables. The drum, in turn, is connected by a cable to the opposite end block. In this configuration, the spring pulls the pulley back, which rotates the drum, which pulls the cable attached to the opposite end block. In this way, the strength of the coiled spring works to move the parallel metal bars opposite the force of the camera's weight.

The advantage of this system is that it's easy to adjust the spring strength to match different weight loads. The cable can be moved up and down on the end block. Moving it up rotates the drum, which pulls the pulley in closer, which stretches out the spring. This increases the pulling force working against the weight force.

The articulated arm essentially acts as a shock absorber for the camera sled. When the operator moves, the base of the arm moves as well. But the spring system in the rest of the arm responds to the weight of the sled. Instead of a sharp jolt, the camera shifts its position smoothly. The arm also frees up the person's hands -- it hangs directly on the vest, so the operator doesn't have to do anything to hold the camera sled up. He or she can concentrate on positioning the camera to get the best shot.

The Steadicam sled is the assembly that actually holds the camera equipment. A Steadicam operator moves the camera by rotating and tilting the sled pole, the central piece of the sled, which connects the various camera components. In the standard configuration, the monitor and battery are attached to the bottom of the sled pole, and the camera is attached to the top. Some Steadicams are reversible, so the cameraman can position the camera on the bottom and the other components on top. This makes it easier to get low angle shots.

In addition to moving with the pole, the camera can be pivoted up or down on its mount (called a sleigh), and in some Steadicams, the pole can telescope up and down. This lets the cameraman get high angle shots.

Other than holding the camera equipment, the sled's primary job is to provide balance. It achieves this by increasing the camera system's moment of inertia, or how resistant it is to rotation. This is determined by two factors: how much mass the object has and how far that mass is from the object's axis of rotation. Increasing mass makes an object harder to rotate, as does increasing the distance between the mass and the axis of rotation (a rolled out slab of clay, for example, is harder to rotate than a tight clay ball with the same mass).

Increasing the object's moment of inertia makes it harder to shake the camera unintentionally. One way to increase the moment of inertia would be to add more weight to the camera system, but this would make things harder for the cameraman. Instead, Garrett Brown decided to take the existing components of the camera and spread them out. This increases the distance between the axis of rotation and the mass of the total camera assembly, making the camera more resistant to rotation.

Expanding these components also shifts the camera assembly's center of gravity, or the point where the object's weight is balanced. When you hold an object precisely at its center of gravity, you can lift the object straight up because the downward pull of gravity is equal in all directions. You can balance a broom on your finger, for example, if you lift it at just the right spot between the bristles and the center of the broomstick. But if you place your finger anywhere else along the broomstick, gravity will pull more on one side than the other, and the broom will fall over.

In an ordinary camera assembly, the center of gravity is inside the camera itself. When you spread out the components, the center of gravity falls between the various pieces of equipment, along the sled pole. In a Steadicam, the articulated arm's gimbal grips the sled pole just above the center of gravity, in order to keep the camera from tilting in any direction on its own. The cameraman typically grips the sled pole at a point near the center of gravity, allowing him or her to control the camera more precisely.

Balancing the sled components correctly is a precision operation. The camera, monitor and battery have to be positioned just right so that the center of gravity falls near the gimbal. To make this adjustment easier, sophisticated Steadicams are outfitted with radio-controlled motors that move the various components by minute increments.

This makes it easier to balance the sled when the cameraman is getting ready for a shot, but it also allows the cameraman to make adjustments in the middle of a shot. This is an important feature, since the sled balance often changes during operation (for example, the weight of the film will shift as it moves through the camera). For some shots, the cameraman may want to shift the center of gravity away from the gimbal, so that the camera leans in one direction on its own. The balance can be adjusted with a joystick mounted on the sled grip, or remotely, with a radio-control unit.

In the next section, we'll see how Steadicam operators put all this technology to work to get remarkably smooth, hand-held shots.

Operating a Steadicam is one of the most difficult jobs on a movie set, but perhaps one of the most rewarding. For a typical Steadicam shot, a camera operator must follow a predetermined path, while simultaneously adjusting the camera and avoiding any obstacles, all the while supporting more than 70 pounds (32 kilograms) of camera equipment. (The Ultra² model's iso-elastic arm has a camera capacity of up to 70 pounds.)

The job requires a good deal of physical stamina, technical skill and a good sense of shot composition. The director plans the shot, but the Steadicam operator makes it happen.

The best technique for Steadicam operation depends on the nature of the shot. To film a simple conversation between two actors, an operator may try to replicate the even feel of a dolly shot, keeping the camera perfectly level and moving it slowly around the action. For a "flying sequence" over low ground, the operator might intentionally tilt the camera from side to side, creating a soaring effect.

One of the most common uses of the Steadicam is to track actors as they move around obstacles or rough ground. Typically, the operator will walk ahead of the actors, shooting them from the front as they walk and talk. For this sort of shot, the operator may walk backward through the scene, with the help of other crew members. Or he or she may walk forward, with the camera pointing behind him or her. Or, heck, he or she may hop on a Segway traveling at a good clip, dismount, sprint up a ramp and then do a 360 around the point of interest (see the related YouTube video here). For these shots, and most any other, the director, the crew and the operator will all work together to figure out the best approach.

Many professional Steadicam operators work freelance, renting themselves as well as their equipment out as a complete package. When a scene in a film calls for a Steadicam shot, the filmmakers will select an experienced operator based on his or her past work. Many established Steadicam operators are members of the Steadicam Operators Association (SOA), founded in 1988 by Garrett Brown. In addition to representing hundreds of Steadicam operators, the SOA holds regular training workshops. Tiffen, the company that manufactures Steadicams, also organizes training sessions.

Steadicam operators have helped create some of the coolest shots in film history.

Martin Scorsese, Paul Thomas Anderson and many other directors have used extremely complex Steadicam sequences to establish mood and setting. In "Goodfellas" (1990), Scorsese employed a Steadicam to bring the viewer into the bustling Copacabana restaurant. In a single five-minute shot, the audience follows Ray Liotta and Lorraine Bracco in the back door, through the kitchen and up to the bar, stopping to meet patrons all the way. It's one of the movie's most mesmerizing sequences.

These stabilizer systems also are used in special effects sequences. For the speeder bike chase in "Return of the Jedi" (1983), operator Garrett Brown walked the camera very slowly through parts of California's Redwood National Park. The special effects crew sped up this footage and combined it with blue-screen footage of the actors on bikes for one of the most exhilarating chase sequences ever filmed. Without a Steadicam, the footage would have been way too shaky when it was sped up.

Steadicams have given filmmakers and moviegoers alike a new freedom of movement. With a Steadicam, a director can float the camera (and, by extension, the audience) into a forest, through a crowd of people, or down into a cave. In TV shows like "ER," Steadicam shots put the audience in the middle of the action, as if they were another character in the show.

Not only have these devices changed how movies are filmed, but Steadicams are now a mainstay in sports. One stabilized camera system, which goes by the name Skycam among others, is now a regular part of U.S. football games. First used with regularity during telecasts of the short-lived XFL, the computer-controlled stabilized camera is suspended by cables above the field and allows viewers to see a game as if they were flying high over the field. The Skycam's inventor was none other than Garrett Brown.

You don't have to be a Hollywood director to enjoy footage produced by a Steadicam. Camera stabilizers have become mainstream and well within the budget of many amateur photographers. In fact, camera stabilizers have shrunk to keep up with increasingly small cameras in the hands of amateurs. Some, like the Steadicam Curve, created for the GoPro Hero camera, are small enough to carry in a back pocket. Snowboarders, skateboarders and outdoor enthusiasts in general love the Curve because it allows them to create short clips of their friends as they do their stunts on the half pipe or in the bowl. The $99.95 price for the Steadicam Curve Black isn't a budget-buster.

Apple got into the video-stabilization game by incorporating the technology on its iPhone 4S and iPhone5. While the footage shot with the 4S is vastly superior to the iPhone 3GS or the iPhone 4, it's the Steadicam Smoothee that may thrill mobile cinematographers. The Smoothee is a plastic stabilizer that hooks up to the iPhone. The phone snaps onto a gyroscopic base attached to a pair of curved metallic tubes that extends downward for balance. As one reviewer said, "the Smoothee is a dream come true for home moviemakers ... " [source: Bookwalter].

Speaking of iPhone 4s, iPad2 and iPad Touch for that matter, we've also seen apps like Luma that would take the wobble out of what would normally be a herky-jerky video shoot. Instagram, however, snapped up the Luma app and incorporated the technology into its Cinema feature. The Steadicam Pro software irons out the bumps in hand-held video, correcting in real time as you shoot [source: Sorrel].

If you're really into cinematography and don't mind shelling out a few bucks, the Steadicam Zephyr may be what you're looking for. Its arm can hold a 23-pound (10-kilogram) camera that allows an operator to swivel the camera smoothly. The arm also can be broken down into two pieces, which makes transporting the device much easier. The price for one of the more expensive Zephyr models tops $11,000 [source: Tiffen.com].

For more information on Steadicams, including video footage of Steadicam operators at work, check out the links on the next page.