Here are a few tips for integrating a dolly into your digital video production.
When trying to get real world situations you often have to stray from the stationary camera position in order to get some of the images you need, maintain a visual style, and shoot for transferring the energy of the scene to the audience. You may want to immediately head toward hand held camera use to be able to add that freedom of motion and versatility that you are looking for, but that may end up making the image too distracting because of the shaking. If you are just intending on tracking moving individuals from any direction you may want to use a dolly, which is a movable platform that you can place the camera on. There are a few things to keep in mind if you plan on utilizing a dolly to capture movement in the scene but limit movement with your equipment.
The important thing to remember is that using the dolly is a camera technique through and through. It is not important enough to consider the dolly as a piece of equipment but instead realize that its use is a camera method choice because there are only certain ways of utilizing a dolly correctly and it will inevitably give the visuals of a scene a very specific design. A dolly is really only effective if you are using it to follow people walking from behind, guide them up front, or capture them from the side while moving in the same direction that you are. You can try to turn the dolly while using it, or the camera, but these have to be very specific motions that are well planned and still follow the same tracking principles as the big three dolly positions.
The most common dolly position is arguably the in front guide, which moves in front of moving people so that you are able to see their front profile. This allows for walking conversations to be captured cleanly without an unreasonable amount of camera movement. Try to keep the dolly at least three or four feet in front of the people walking and make sure that you maintain a constant speed. This means that you have to communicate with the actors to keep their pace constant. If either party messes up their pacing they must then scrap the take and start over.
Wheels and Suspension
Make sure that there is both softness in the tires and good hydraulic shocks to absorb any roughness in the floor or outdoor ground. Even the smoothest concrete has imperfections in it and you need to compensate for those if you want a smooth video. The most important thing is that the wheels are rubber and not any kind of hard substance otherwise the visuals will be useless.
The most important thing to keep in mind about a dolly is when not to use one. If you have access to a full steadycam system then you may want to try this for guiding and following tracking shots, but really only if there is a lot of movement from the straight path.