Camera dolly

A camera dolly is a specialized piece of film equipment designed to create smooth camera movements. The camera is mounted to the dolly and the camera operator and camera assistant usually ride on it to operate the camera. The dolly is operated by a dolly grip who is a dedicated technician trained in its use.

Movement

The camera dolly may be used as a shooting platform on any surface, but is often raised onto track, to create smooth tracking shots on the horizontal axis. Additionally, the dolly usually has a hydraulic arm that raises and lowers the camera on the vertical axis. When a dolly grip operates a dolly on both axes simultaneously, this is known as a compound move.

Dolly moves may also be executed without track, adding a third axis and the highest degree of difficulty for the operator. These are called dancefloor moves and may either be done on an existing surface, if smooth enough, or on a special floor installed by the grip department made of a bottom layer of 3/4-inch birch veneer plywood and a top layer of 1/4-inch masonite.

Many types of camera dolly have several steering mechanisms available to the dolly grip. The typical mode is rear-wheel steering, where the front wheels remain fixed, while the wheels closest to the operating handle are used to turn. A second mode, round steering, causes the front wheels to turn in the opposite direction from the rear wheels. This mode allows the dolly to move in smooth circles and is frequently used when the dolly is on curved track. A third mode, called crab steering, where the front wheels turn in the same direction as the rear wheels. This allows the dolly to move in a direction diagonal to the front end of the dolly.

Types

Location dollies are smaller, lighter and designed to fit through standard size doorways. These are the first choice for "on location" work, where it is necessary to carry the dolly up stairs, etc. Studio dollies are larger, more stable and have stronger hydraulic arms. These are the first choice for studio and backlot work where carrying them around is not necessary and stability and comfort are a primary concern. There are also dollys that are being prototyped and have an air bag underneath that allow the dolly to float.

Track

Dolly track is available in steel and aluminum. Steel is heavier making it more cumbersome to work with. It is also cheaper to rent, and steel rental track is often more used and thus more abused. Longer track segments, while heavier, allow track to be laid straighter with less effort. Curved track is also available in different radii.

External links

* [http://www.cartala.com/diy.php Derek W Beck's homemade dolly design]
* [http://www.jorenclark.com/studentfilms/dolly/dolly.html Joren Clark, Do It Yourself Dolly] Another example of a homemade dolly
*http://www.digidolly.com.au Digidolly. The leaders in light weight camera dolly systems
* [http://www.elurauser.com/articles/centi_dolly.jsp A simple dolly made of PVC pipes]