Steadicam is a Camera stabilisation device capable of reproducing the smoothness of a Dolly shot, whilst maintaining the extreme manoeuvrability of a 'Handheld' Camera.

It allows the Camera to seemingly float beside the Operator, the entire weight of the 'Rig' being transferred to the Operator's hips by a sprung arm.

There are no 'Gyros', the system works by increasing the Inertia of the Camera. By making the Camera a larger, heavier object it resists the Operator's body movement.


Inertia is a very useful property to a Cameraman, heavy objects require more force to move them or change their direction than light ones. This is why a heavier handheld broadcast camera feels so much smoother than a domestic camcorder.

Spreading the load further increases Inertia. If you carry a suitcase, it moves along quite happily with you. Carry the same weight but make it longer like say, a wooden ladder and it seems to develop a life of it's own. It refuses to turn corners with you and can only be persuaded with slow deliberate movement.

The ideal high Inertia system is to split the maximum weight you can comfortably carry into two lumps and to put them at either end of a long lightweight pole, dumbbell fashion.

But this Inertia is only useful in the plane of the pole which can still roll violently on its axis. The Steadicam goes one step further, it splits its weight into three lumps and arranges them in a triangular fashion.


There are four main components to a Steadicam; the 'Sled', the 'Gimbal', the 'Sprung Arm' and the ‘Vest’.

The sled consists of an adjustable Camera 'Stage' mounted on a lightweight, telescopic carbon Fibre 'Post'. At the bottom of the Post are the Monitor and Battery mounted on sliding rails set at right angles to the Post.


This triangular placement of these heavy components is the secret of the Steadicam system. Increasing the separation between the Camera and the Battery / Monitor provides more Inertia resisting rolling in the vertical plane. Likewise increasing the separation between Battery and Monitor produces more Inertia in the horizontal plane.


The triangular design also means that when correctly balanced, the 'Centre of Gravity' of the whole sled lies somewhere along the Post.

The entire weight is supported by the 'Gimbal' which is set just above the Centre of Gravity so that the Sled is slightly bottom heavy and so eventually finds it's own horizon.

The Operators hand grip is directly below the Gimbal giving the Operator fingertip control exactly where he needs it, on the Centre of Gravity. Placing the handle at this point means that only the lightest fingertip control is needed to steer the Sled. Gripping the handle tightly upsets the stability of the System.

The Camera can be adjusted left and right across the Stage to set the horizon. It can also move Fore and Aft to set the headroom.

 

The Gimbal contains 3 sets of near frictionless bearings that allow complete freedom of movement whilst supporting the entire weight of the Sled and Camera.

The Gimbal is permanently mounted to the Post on a lockable sliding collar, the coupling to the Sprung Arm at the other end is moulded into a second handle.

The bearings allow the Operator to manoeuvre around the sled during a shot while the Camera remains framed on the subject.


The Operator's body movements are absorbed by the 'Sprung Arm' which is docked onto the 'Vest' via a hinged coupling.

Working on a similar principle to an 'Angle Poise' lamp the springs can be adjusted to just support the weight of the Sled.

 

The Arm has two Parallelogram sections hinged in the middle, each concealing an array of Titanium lifting springs known in the USA as Dampers, all connected by cables and pulleys.

This Parallelogram design ensures that the attitude of the Gimbal coupling mimics the attitude of the Vest's chest plate.

Walking or running vertical motion is absorbed by the dampers . Side to side sway is lost in the arm’s hinges.

A good operator controls the movement of the rig with his body attitude. Shift your weight forward and the rig starts to fly forward away from you, once you catch up with it shifting weight backward arrests its motion. The same is true for left and right movement.

Again Inertia is helping us as the heavy floating Sled requires more force to influence it than the springs can transfer. So even though the operator's body and most of the arm can jiggle around wildly during a shot, the Gimbal and Sled remain suspended in space.

The padded Vest is tightly worn by the Operator, it has wide shoulder straps and body straps that run around his chest and waist. These straps are tightened with a clever ratchet buckle system and undoing the ratchets relieves the Vest pressure between takes.

The Vest is held together on the back by large Velcro pads attached to a Rip Chord, mainly of use if the Steadicam is to be used near deep water or at a height.



The Sprung Arm docks with a casting called the ‘Socket Block’ which is bolted onto a horizontal plate known as the ‘Bridge’. The bridge is dovetailed to a metal chest plate called the ‘Spar’.

The Socket block has adjustments that act in the same way as a Head Leveller, allowing the rig to be set to match the Operator's body posture.


We have looked very basically at how the Camera 'Stage' can be adjusted to balance the Sled and how its Inertia can be controlled for specific shots by lengthening the post and sliding the battery and monitor in and out on their rails.

Even then the relationship of camera and battery positions can lead to problems once the rig is in motion. What balances well when static can heel and yaw badly even during a slow pan.

A back heavy camera can simply be offset by sliding the monitor forward. However when panned the centrifugal force will pull the back of the camera and the front of the monitor apart with instant loss of control for the novice operator.

Ideally the Camera needs its centre of gravity to sit directly in line with the post and must then be equally balanced out with the Monitor and Battery adjustments. This is the realm of a black art known as 'Dynamic Equilibrium' although a 'Suck it and See' technique of moving Monitor, Battery and Camera in turn usually cures this problem eventually.

The careful setting up of a Steadicam is the key to its optimum performance. If an operator does not know how to properly set up each of the components we have discussed, he will effectively spend all day fighting his rig.

A good Operator on the other hand, with a properly tweaked rig can fly his sled around a set without touching either the arm or the post. He is able to completely change direction and even walk around the rig, his hands are really only needed to lightly pan and tilt the sled and control the height of the Sprung Arm.

The resulting 'Steadicam Tango' is a joy to see and the ever expanding repertoire of otherwise impossible shots never fails to impress.