Tripod Head Theory
A little history: Correct me where I am wrong. Before fluid heads there were
gear, free and friction heads. Then came the Akely clockwork head that used
the inertia of a set of gears and a flywheel to smooth out pans and tilts. Then
Chad O' Connor designed his fluid head to smoothly shoot racehorses. Miller,
ITE, Ceco and others made tightly sealed cylinders with viscous fluid that gave
only one degree of dampening also dependent upon the temperature. Ron Ford designed
a fluid head using fluid encased disks that could be engaged to vary the degree
of fluid resistance. Sachtler
and others followed.
Some theory: Early camera before sound were lightweight and had no inertia to
smooth out their starting, stopping and continuing a move. Mitchell, Bell and
Howell and others made small gear heads that made smooth moves possible. Large
cameras, especially the early TV cameras were large enough that their mass provided
enough inertia to make smooth moves possible on free heads. (Free heads have
no fluid dampening, only friction which is not very helpful to smooth moves
.) Cradle and gear heads with some operator skill made very good moves possible
with these dog house sized like the Techicolor blimp cameras.
When TV cameras got smaller and lighter, video operators found they needed fluid
dampening to control their moves. Today we have a great collection of heads
at all prices.
Inertia: It takes energy from the operator or grip to get a heavy camera, crane
or dolly moving. Unless damped by friction or fluid, inertia will keep a camera
or it's support vehicle going smoothly until the operator or grip applies energy
to force the crane or dolly and camera to a smooth stop. Any friction must be
overcome with an equal continuing force.
"FLUID" DAMPENING: Viscous fluid, like STP, between two surfaces gives a smoother
response to the camera than simple friction. Chad O'Connor first used a system
similar to a car wheel bearing, brake drum, and cork brake shoe dipped in viscous
fluid and sealed to keep the goop from leaking on the operator. These heads
are still around and still working just as well today. The O' Connor 50 used
a brake band and gave a lot of dampening for an extremely lightweight, strong
head. (If an O'Connor gets stiff it needs cleaning and new fluid.) The new line
of O'Connors with spring counterweight adjustments is a real jump ahead in technology.
SPRING TENSION: Springs are needed to offset the weight of the camera above
the tilt pivot point. Earlier camera heads came with fixed springs. Today better
heads allow spring tension adjustment to balance the camera weight so that the
camera will remain in any tilt position when the operator lets go of the pan
handle. The camera won't droop or the operator won't have to fight to pan up
NODAL HEADS: Nodal heads, like the Ron Ford and Weaver/Steadman, cradle and
cradle gear heads (Worrall) don't need counter weight springs because the camera
weight is supported and balanced about the tilt axis. These heads also have
use for effects work where the axis of the lens must be constant. (Hence the
The Weaver/Steadman nodal head can be configured in any way to facilitate putting
the camera where you want it. The Ron Ford nodal head is not as strong for bigger
cameras and longer lenses.
GEAR HEAD: Once an operator has learned which way to turn the wheels instinctively,
the camera almost moves by reflex almost without the operator thinking, like
steering a car. Unfortunately with the studio training gone, working the way
up from loader, it's harder to get ones hands on a gear head to practice. Someone
should design or convert something into a cheap practice head to train on. It
only needs one speed and even a limited move. One could use a camcorder or still
camera as a view- finder.
GIMBAL TRIPODS AND HEADS: Nelson Tyler, Clairmont and other have made these
counter weighted tripods to allow shooting with a level horizon on large ships.
They won't work on small boats that roll too quickly.
REMOTE HEADS: Light weight cranes and remote heads have made possible moves
that were not possible a few years ago. Even though these do not carry an operator
and assistant, they are just as dangerous because of their size. Here is where
an experienced crew and operator are absolutely necessary.
If you are using a tripod head as a pivot for an arm, let inertia provide dampening
and not fluid or gears at the center. Extended weight on arms on a gear head
will often chatter. (See
Shooting Out Small Windows)
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.