During filming sequences with a motion picture or video camera, it is often necessary for the camera to be moved over a floor or ground surface. This movement must be accomplished smoothly. Even small amounts of shock or vibration transmitted to the camera lens can result in shaky or erratic recorded images.
One technique for achieving smooth camera movement is to support the camera on a camera cart, dolly or crane which moves or rolls over rails or track. However, installing track is very time consuming. Placement of the track may also interfere with camera angles, since in most filming sequences, it is important that the track must remain out of the field of view of the camera. In addition, after the track is laid, the dolly is necessarily restricted to movement purely along the track. Even small changes to the path of movement of the camera (as may be spontaneously requested by the director, cinematographer, camera operator, etc.) cannot be achieved without changing the track layout. As a result, track is generally only used when absolutely necessary, such as where smooth movement over a very irregular surface (such as sand, gravel, unpaved outdoor surfaces, etc.) is needed.
Due to the need for an extremely stable camera platform, even relatively smoother surfaces, such as paved surfaces, or indoor flooring, can create difficulties in achieving satisfactory filming. The motion picture or video camera is typically mounted on a camera crane or dolly having wheels which roll over the floor or supporting surface. Irregularities in the floor or supporting surface (for example, cracks, bumps, depressions, debris particles, etc.) generate shock and/or vibration impulses which can be transmitted through the structure of the dolly to the camera lens. These impulses degrade steady filming ability. In addition, since the camera is typically positioned substantially above the floor surface, the effects of a small crack or bump in the floor surface can be magnified at the camera position. To reduce the effects of irregularities in the floor surface, camera dollys and cranes having soft tires have been used. However, soft tires cannot eliminate the effects of larger irregularities in the floor surface. In addition, soft tires increase rolling friction, and make the dolly more difficult to move or steer.
The shock and vibration isolator described in Chapman, U.S. Pat. No. 4,989,823, incorporated herein by reference, has successfully been used for several years. This isolator design is very effective in isolating the camera from lateral (side to side) and longitudinal (front to back) shock and vibration impulses. It has been widely used with very good results on camera dollys. However, this isolator design has only limited ability to prevent vertical shock or vibration impulses from reaching the camera.
Accordingly, there is a need for an improved device and system to allow for smooth filming sequences.
Many camera cranes and dollies have a leveling system for keeping the camera platform in a level orientation as the crane or dolly arm pivots up or down. Typically, these leveling systems use a parallelogram linkage, with examples described in Chapman U.S. Pat. Nos. 4,360,187; 5,816,552; 6,345,919 and 6,450,706, incorporated herein by reference. These parallelogram leveling systems keep the camera platform locally level, that is level or parallel with the vehicle, such as a crane or dolly that they are mounted on (and not necessarily level with the ground). However, when the dolly rolls over an irregularity, such as a bump or crack, the dolly is momentarily inclined at a slight angle. This movement, or elevation angulation, causes the camera lens to also be momentarily inclined at a slight angle. This disturbance of the camera lens can become unacceptable, especially when filming distant subjects with telephoto lenses. Accordingly, there is a need for an improved camera platform leveling system able to better compensate for angulation.