Using a Camera Dolly
Having watched years of professionally produced movies and television shows, audiences have high expectations for what they see on screen—they take for granted that all camera movements will be smooth and every shot will be steady. If your camera has the slightest shake, people will notice. In addition to mastering the technical aspects of digital video (frame rate, aspect ratio, color balance), producing a good show requires precise camera control to get the motion effects you want.
For years, this meant using expensive rigs and elaborate setups ranging from specially equipped trucks, to cameras mounted on dollies that rolled along a track, to robotic cranes that moved cameras by remote control. Needless to say, these were not cheap. The affordable options were to shoot handheld, which resulted in shaky images, or to mount the camera on a stationary tripod, which produced smooth pans and tilts but limited mobility. Then came the Steadicam.
6.1. Stabilizing a Moving Camera
A Steadicam (www.steadicam.com), shown in Figure 6-1, is a camera stabilization system that mounts a camera on a rig, called a sled, and balances the camera using a monitor and battery pack that hang
underneath and serve as counterweights. The rig lowers the camera's center of gravity, and the design of the Steadicam isolates the camera itself from the operator's movement.
Figure 6-1. A Steadicam and its operator.
In the full, professional versions, the Steadicam attaches to a harness, which distributes the camera's weight and allows a cinematographer to operate a large, heavy camera for extended periods of time. (Even with the harness, Steadicam operators have to be fairly physically strong.) The Steadicam sled connects to the harness through a spring-loaded arm that enables an operator to move freely without causing any camera bobbles, or shaky images (a practiced operator can even run or climb stairs). The resulting shots look as if they were captured by a camera floating in midair. A talented cinematographer can achieve fairly stable
results with a handheld camera, but in close-up shots, even the slightest camera movement becomes especially noticeable.
A high-end Steadicam is by no means cheap; the list price for the top model is more than $65,000, but with the advent of high-quality prosumer DV camcorders, the company began to offer more affordable models.
The scaled-down Steadicam Mini, for cameras that weigh 5 to 15 lbs (such as the 6.5 lb Cannon XL2) lists for $5,500. There's also a handheld Steadicam JR for cameras 4 lbs or less (such as the Sony VX2100 or the Panasonic AGDVX100A). The Steadicam JR, which does not attach to a harness, lists for well under
$1,000, falling solidly into the prosumer price range.
The Steadicam JR's setup manual (available online free of charge at http://www.steadicam.com) compares the function of a Steadicam to balancing a cereal bowl on the tip of your finger, as in Figure 6-2. The manual explains that balancing the bowl is difficult, because its center of gravity is higher than your finger.
If you turn the bowl upside down, the manual points out, balancing the bowl becomes significantly easier (even while moving your hand) because the bowl's center of gravity is lower than the tip of your finger.
Even if you have no interest in balancing a bowl on your finger, the comparison provides a great
explanation of the principles behind the Steadicam's operation. Placing the weight of a monitor and battery pack at the bottom of the rig helps balance the weight of the camera on top, making it easier to stabilize.
Figure 6-2. A person attempting to balance a bowl on the tip of a finger. In the first image, the bowl is upright, and the person's finger is on the bottom of the bowl on the outside. In the second image, the bowl has been turned upside down, and the person's finger is inside the bowl, which lowers the bowl's
center of gravity and makes it easier to balance.
In both the handheld and body-mounted versions, the sled connects to the rest of the rig through a gimble, which provides a full, flexible range of movement. The construction of the gimble, which Steadicam operator Lou Rosenberg describes as the "guts" of the Steadicam, enables an operator to smoothly tilt a camera forward and backward, lean it from side to side, pan the camera as if it were on a tripod, or execute any of these moves in combination. A gimble is shown in Figure 6-3.
Figure 6-3. The gimble is the "guts" of the Steadicam.
Steadicam is a brand name that, in everyday speech, has erroneously become a generic word for any type of device that keeps a camera stable during complex movements—much like Kleenex has come to mean tissue. (Some companies love this. It means they are at the top of their field. Others hate it and feel it dilutes their trademark.) Other companies offer competing stabilization systems, both handheld and harness based. For example, a company called Glidecam sells the Glidecam 2000 Pro handheld stabilizer for cameras that weigh up to 6 lbs, and the handheld Glidecam 4000 Pro for cameras that weigh 4 to 10 lbs.
These two systems retail for $369 and $499, respectively. The same company also sells the Glidecam V-8, a harness mounted system for cameras that weigh up to 10 lbs, which lists for less than $3,000. Other companies, such as VariZoom and Hollywood Lite, also offer similar products.
Note: There is a web site called "$14 Steadycam [sic]—The Poor Man's Steadicam"
(http://www-2.cs.cmu.edu/~johnny/steadycam/) that shows you how to build your own camera stabilization device. The site gets its name because the parts, most of which are available at your local hardware store, cost about
$14. While this isn't a true Steadicam ("Steadicam" is a trademark of the The Tiffen Company, LLC), this
"$14 Steadycam" offers a possible low-budget solution, especially if you like to build things yourself.
The advent of the Steadicam introduced a new kind of shooting. In love scenes and music videos, it's become common to see the camera make smooth 360 degree revolutions around the star, providing a dizzyingly beautiful shot that never would have been possible without a stabilization system that was easy to move. In the pre-Steadicam era, filmmakers could circle around a subject by mounting the camera on a dolly, and placing the dolly on a circular track. Track-mounted dollies can move in extremely smooth circles, so a director using one could get great shots, but the circular movement was fixed—the camera could only move around the set path of the track, and if the actor moved beyond the circumference of the track the shot wouldn't work. If a director wanted to stage shots in more than one location, or from multiple angles, the crew would have to reassemble the track for each new shot. As you can imagine, this limited the type of shots available to a director, even in the most carefully staged production, and made the use of tracking shots generally impractical for most documentary work.
The Steadicam and Glidecam, however, enabled smooth movement through crowds; stable camera work on uneven surfaces like stairs or outdoors on rough terrain; and created a whole new type of chase scene where the Steadicam operator runs along side the actors without shaking the camera. The Steadicam has also
enabled filmmakers to shoot great tracking shots from any type of car, pickup truck, or motorcycle, even from a golf cart. Large-budget shoots often employ cranes or cherry pickers for aerial shots, and artful cinematographers can combine them with a Steadicam to get truly impressive results—more than one episode of ER contains a breath-taking shot captured by a Steadicam operator who walks onto or steps off of a moving crane partway through a take.
Affordable camera stabilization has also made its mark on small-budget independent works, student films, and even weddings and birthday party videos. Fluid, stable shots have become the norm to such an extent that jerky camera movement is often reserved for especially chaotic chase scenes or for building tension in horror films. In The Shining, director Stanley Kubrick followed his young protagonist with a slightly wobbly camera as he rode laps around the empty hotel on his low-rider tricycle, evoking remarkably unsettling feelings in his audience long before anything overtly frightening showed up onscreen. Stable camera work has become such a convention that the Coen brothers invented a Shaky-cam, a camera mounted on a plank of wood with a person holding each end, designed to produce noticeably un-Steadicam like images for dramatic effect.
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