Hi Ken,

The glideshot products look pretty serviceable.

To let you know where I'm coming from, I worked as a grip for about 15 years before opting for a steady paycheck in 2001. Many of those jobs I worked specifically as a dolly grip. I've worked with the smaller chapman and fisher units, with skateboard dollies (most grips refer to the glideshot stuff as skateboard dollies) and I've also worked with small cranes and jibs, both ride-on and remote. There are surely others with more experience but I've got a lot. So here's the treatise on what to look out for with the glidecam unit.

First off, they look just fine for what they are... a dolly an individual could afford to own.

What you want in any dolly is rigidity and smooth movement.

For rigidity, you want a dolly that won't flex if you ride it because that changes the leveling of your camera, and that's often important for product shots. Leveling a camera before the operator steps onto the dolly might just be a waste of time.

You also want push-pull handles that are rigid. If you pull on a handle and it flexes then this can affect your shot. Often you can fix this with diagonal bracing or by mounting the handle diagonally so you're pushing down it's length.

If the operator is standing on the dolly he or she may sway or shift their weight, causing a surge or braking of the dolly move. If possible, try to arrange for them to sit.

As for the wheels...these skateboard wheel arrangements have been pretty popular for a while now. The most common concern is that the wheels may deform if the dolly sits to long. You'll often see a dolly grip rock the thing back and forth periodically to try to prevent this.

These wheel sets aren't designed to go around curves. To do this, the four sets of wheels usually have to change their positions relative to each other. Imagine you fixed the wheels to a perfectly square frame. When you start to round the curve that square would like to stretch into a rhombus (and of course the wheels need to turn as well). With loose PVC you'll find that the track tends to shift when rounding a curve.

Anyway, the glideshot people say repeatedly that the wheels are designed for straight track. They get points for honesty.

Once you've got a simple dolly built or bought, the whole game is in track setup. If you're shooting big things or big action you can get away with a pretty marginal track run. For smaller products, the track needs to be layed as level as you can get it.

Let me illustrate a typical dolly move for a tabletop shot. The director or operator gives you instructions that amount to moving 6' over 6 seconds. That's a slow move. The camera and tripod are on the dolly, strapped down tight, and the operator is sitting on an apple box on the dolly.

The camera rolls and the operator gives you the cue to go. You start the push with your arms and shoulders (a press). This is the point where you change the state of the dolly and operator from stationary to moving and it takes a little more force than it would to just keep the dolly moving. Unfortunately for you, you're going so slow that you're always in that state of change (you're almost not moving) and any good fidget of the camera operator can stop you dead.

You're moving and counting, things are going well, until you come to a spot where the track is dipping. You should have leveled the entire thing but you were in a hurry. The dolly is now going just slightly down hill and you are trying to slow it down just a little to keep the speed constant. Of course the problem is that this is a dip in the track and now you're climbing out of it and you were just trying to slow it. The dolly stops dead. Crap.

This is one reason why there are many takes to a shot. And the reason why well prepared track can be vital to a precision shot.

Point? Maybe there really isn't one in that little annecdote but there are definitely some tricks to a good dolly move and hopefully I've got your imagination going a bit.

Rob Mack