Isolating Camera Vehicle Motions
Every vehicle and support system
has different motions to isolate from the camera. Any reduction of unwanted
vehicle movement helps the camera system work better. Camera cars use the mass
of the turret and weight box to help stabilize the camera, operator etc. Lightweight
remote head arms on camera cars are improved by a spring-loaded vertical shock
absorber on the post that helps isolate road bumps from the arm. Jim Dickson
does this. As vehicles and dollies go over bumps there are various motions that
inertially stabilized mounting of the camera about its CG and tripod head will
improve. (See Professional Rigging Inertial
Factors: 1. If the camera is relying
on the inertia of a vehicle for stability, the camera and tripod or rigged support
needs to be well supported to the vehicle so that the camera doesn't move separately
from the vehicle. Weak tripod legs supported on flexible metal panels or a tripod
head that is too small doesn't help. Of course the tripod or camera support
rigging needs to be well tied down. For a tripod it is best to tie it down at
the bottom of each leg if possible.
2. Focal length is very important.
A 1-degree shake would hardly be seen on a 60-degree wide angle shot, but a
disaster on a 3-degree telephoto shot. A level and steady horizon is important.
Horizon correction is handy. A strong ball leveling head helps. The camera can
usually bounce up and down vertically and not be objectionable if the horizon
is stable in the frame. (See Professional Special Effects Feeling
3. A camera high above the wheels
of a dolly rocks back and forth as a wheel goes over a bump on dolly track or
on the ground. If the camera is on top of a fluid head with counter balancing
springs, the camera tips because the C of G of the camera is above the pivot
point of the fluid head. The Chapman Vibration Isolator will eliminate this
motion. A gear head, strong nodal head (Weaver Steadman) or (see Professional
Rigging Inertial Tripod Head) described
in this site will reduce or eliminate this motion. The wider the spread of the
wheels of any dolly the less bumps on the track or on the ground will effect
the camera. A narrow doorway dolly with a high camera will sway a lot on grass
or rough ground where a wider wheel dolly will be much more stable. Attaching/tying
down the tripod spikes as close as possible to the wheels helps eliminate any
flex in the dolly frame such as a plywood skate board model or one made out
of go-cart wheels. Consider a modular go-cart wheel dolly made out of Speed
Rail © to allow a wide adjustable wheel base. Also provide support for
the operator so his body doesn't bounce around. It will help him judge stability
of the shot and prevent his body motion effecting the smoothness of the shot.
Apple boxes tied to the dolly to sit on will help.
Cars: Old luxury gas-hog sedans and
station wagons are very stable. Taking a Sawsall or cutting torch to one can
create an ugly but stable camera car. They won't support an arm for the operator
and assistant but might support a remote arm. A professional camera car is designed
to provide room for everybody to work. With a camera car you also get (almost
always) an experienced driver that is aware of safety and knowledge of what
can be done reasonably and efficiently. Some trucks are well sprung and can
be used. Weight helps smooth out stiff suspensions.
4. Large Ships roll slowly enough
that a pendulum tripod system like Tyler's or Clairmont's will compensate for
the slow rolling with simple gravity. Sometimes an operator can compensate for
the ships rolling if shooting objects broadside off the ship in calmer seas.
On a set, a "Dutch" head will help recreate the rolling effect.
5. Smaller Boats roll about an axis
approximately around the center of gravity and hull curve of the boat, but at
a higher rate than a pendulum system can compensate for. An operator supported
inertial system can work in some conditions. (See Inertial Camera Stabilization
Collar) A camera on a tripod is not very useful at very much speed or on
a rocking stationary boat. For flat water two flat bottom duck boats lashed
together with strong beams is very stable. "Vee" hulls like catamarans are not
as good as lightweight flat bottom boats. The wider the boats or hulls are,
the more stable the platform is. Consider an outrigger off of one boat. It could
be a plank floating flat in the water. Use stiff beams to support it to avoid
motion between the boat and outrigger. (See Professional Production Technique
Shooting on Water)
6. Airplanes suffer mostly from air
disturbances that rock the plane about its fuselage axis. This shows up most
on the horizon in camera. Wider lenses helps and shooting higher speeds helps.
A STOL like the Helio Porter with long wings is much more stable than a Cessna
piston plane. Rigging a camera support securely to the floor or seat rails of
the plane helps. There are cargo tie-down clamps that attach to seat rails on
the floor. You can also make tie down clamps out of angle aluminum, bolts and
"S" hooks. Removable cargo doors such as on a Cessna 206,207 or 208 models make
shooting out the side easy. Wind deflectors are FAA required when flying with
the cargo doors off and to reduce airflow through the plane. (See Professional
Rigging Technique Shooting out of Small
Shooting early AM helps when the
air is usually smoother and the light is better too. An intercom with the pilot
and/or director is very helpful. Dress warm, carry maps and discuss before take-off
with the pilot what you are looking for. I found it easier to explain changes
to the last shot you just tried easier than trying to describe a whole new shot.
7. Helicopter bodies oscillate below
the supporting blades. Bigger ships are more stable. Tyler mounts and gyro stabilized
systems work well. Well-balanced helicopter blades help. The more blades the
smoother the ship and clearance below the shorter blades is increased especially
with forward motion. (Hughes) Crop dusters don't worry much about balancing
their blades and often don't understand much about camera moves.
8. The Human Operator's body drops
and rises in height as he walks. The smaller the steps the smaller the drops.
There is also a front to back motion and if the operator's eye is against the
eyepiece that can also introduce motion to the camera.
9. The mass and inertia of Chapman
cranes and Fisher and Chapman dollies help stabilize the camera. The risers
and extension arms supplied by them are usually strong enough if used properly.
If you offset or extend an arm, balance the camera weight with a counter weight.
It will reduce the strain on the dolly and make the camera more stable. 1-1/4"
Speed Rail © isn't strong enough to support heavy cameras and heads as
extensions. 2" IPS aluminum pipe starts to be strong enough. 1-1/2" steel pipe
is strong enough. (See Professional Rigging Technique Pipe,
Tube and Conduit)
10. Bicycle Wheeled Vehicles are
lightweight and can work where other vehicles are not allowed such as on running
tracks. Consider trailers or three wheel rigs. Bicycle wheels with 3/8" or 5/16"
axles must be supported from both sides. Older coaster brake wheels can be outfitted
with internal ball bearing and large enough shafts to be supported from one
side only. Wheel chair wheels and industrial wheels can be supported from one
side. 1-1/4" Speed Rail © is very useful to build these vehicles. Old bike
frames can be cut up and welded. The peddle crank housings can be joined with
tube and long threaded rod in the middle.
Bicycles are well designed to be
ridden, but it is a challenge to rig a heavier camera on them. Consider all
the shots that could be done from a regular dolly, golf cart, rigged side car
or car with a bicycle being towed along side or behind.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.