Operating a Camera on Cranes and Dollies
(With comments by Bill Bennett)
Getting practice on a studio crane is often not easy. Learning where to place
the "post" of a crane and make good moves can be learned with a cheap
or even homemade arm. With lots of practice, the camera will compose what you
want it to without you consciously thinking about it. Like backing up a trailer
while looking through the rear view mirror. Good camera operators whether riding
on the crane or operating a remote head make moves by reflex learned with practice.
Like using "the force" ™ and not thinking about it. Like driving
a car or hitting a ball.
Something to always remember when setting up, transporting
or operating a crane: NEVER allow the arm to come anywhere near overhead power
lines. You can find these on most utility poles in towns and cities, as well as
on transmission towers out in the countryside. Remember, the arm doesn't have
to actually touch the line for the deadly current to flow. Depending on the voltage
in the lines, the power can jump many feet from the line to the crane arm. Never
set up under power lines, even if you never intend to raise the arm that high.
Incidents have occurred where the operating crews have lost control of the arm,
it rapidly rose near the wires and very unfortunate things happened as a result.
The best situation for operating a camera on a crane or dolly is riding with the
camera tripod head and moving as the camera moves. This happens on large studio
cranes where the camera operator, assistant and sometimes the director ride. On
smaller hydraulic stage dollies the operator is raised and lowered only partially
as much as the camera. He has to make body adjustments to keep his eye up to the
eyepiece. Modern cameras have pivoting eyepieces that help make up for this problem.
On a crane the operator must compensate for the natural movements of the arm.
When the arm moves up from the ground the camera moves away from the post position,
and closer to the subject. As the arm passes level
with the top of the post and continues higher, the
camera starts to move closer to the post position. If the arm is moving in a circle,
the motions are similar. The arm gets closer to an object when the camera is pointing
straight off the end of the arm. As the arm swings away from the object it gets
farther away and panning is necessary to keep it in frame. If there is both an
arm move up and to the side the corrections by the operator are complex. These
are skills learned only with experience. They can be learned on a simple arm with
a camcorder.
An operator standing on the ground needs a video monitor as he guides the camera
either by remote control or mechanical means. Operators used to gear heads have
the reflexes to correct for unwanted moves generated by a crane arm panning and
moving vertically. Operators used to using joysticks on even video games have
some advantage using a similar remote control device. A few remote controls use
a tripod handle control that helps an operator used to such heads and not trained
on gear heads or joysticks.
For any crane, practice is very wise so the operator can keep good composition
of the shot while watching for unwanted equipment in the shot AND be able to judge
the action within the shot. Directors are usually watching for the performance
and do not notice when the camera is off the set or a mic is in the shot.
On dollies, if at all possible the operator should ride behind the camera. He
should be comfortable and seated if possible. If his body is resting against part
of the dolly it helps. He should not stand unsupported in some way. Then he will
be able to judge the smoothness of the shot and his body not contribute unwanted
motions to the dolly caused by his body moving around as the dolly moves. If no
support is possible and the operator must stand he can spread his legs to help
stabilize his body.
If there is an arm attached to the dolly, the operator should use a remote finder
if the move is very large. Moving his body can effect the stability of the shot.
Placing the "post" (the tripod head or pivot point) in the best position
of an arm/crane/jib for camera is an art learned with practice. Because the arm
changes position of the camera as the arm moves up and around in a circle, finding
a good starting and ending position for camera is a challenge. If the subject
being photographed is stationary, the "post" must be carefully positioned
to get a good start and end compositions. It is helpful to start with the camera
at right angles to the subject or straight in line with the arm is helpful to
avoid more difficult camera corrections during a move.
Most crane moves can be accomplished with the crane base
stationary. Once you start moving the base as well as the crane arm the situation
becomes much more complicated, unless the floor is very smooth, you will need
to lay dolly track. Even with track any small bumps will become amplified at the
end of the arm. Assuming your crane base will be stationary during the shot, a
lot of time gets wasted when the cameraperson and the director "fish"
for the proper crane base placement to achieve the shot they desire. This becomes
slow and dangerous if the ground where the crane base is to be placed is not level,
requiring the base to be leveled with wooden "cribbing" each time it
is moved. When fully loaded crane bases are on unlevel and/or soft ground, they
are prone to topple over. Many people have been severely injured or killed by
cranes that have toppled over.
Here is a great method to quickly find the position of the
crane center post that works for the camera move you and the director have in
mind: With the crane out of the way, off to the side of the set, take a piece
of rope and tie two knots in it that are the same distance apart as the measurement
from the center of the crane post to the camera lens when the camera is properly
mounted on the crane. Then you have one person stand without moving with one knot
in their hand at what is your first guess at the crane center post position. Then,
with your viewfinder and lens of choice, or camera in hand if it is small enough,
extend the rope full length to the knot which you hold in the same hand as the
viewfinder and stand in your first camera position, looking through the viewfinder.
If you cannot achieve your first camera position with the rope taught, you have
to move the post position person. When you have found your first position of the
move, with the rope taught, and the center post person not moving, move through
your proposed arm move, while keeping the rope taught, to the ending camera position.
Use a stepladder at the beginning or end of the move if required to achieve proper
camera placement. You will probably find that you will need to "jockey"
the post person's several times while making several attempts at the move until
you achieve good starting and ending positions, as well as a suitable path for
the camera during the move. After you have found the proper position for the center
post using this technique, you then put a tape "X" on the ground where
the center post person was standing. Then you place the crane base so that the
post is directly over that spot, and you are done. With a couple of rehersals
of the arm movement, you should be ready to shoot in short order.
If a crane arm moves straight up or down the horizon does not change position.
But unless the camera is pointed straight off the end of the arm, objects close
by need a correction to be kept them centered in the frame. As the arm moves up
to a level position objects move one direction in relationship to the camera position.
Once the camera moves past level the object moves the other way in relation to
the camera. The operator has to compensate for these moves. This is called "crossing
the arm". Practice will make this correction automatic in the operator's
reflexes.
Keeping the horizon level is not a problem if the arm has a leveling arm and the
post is vertical, but keeping distant object in the same relative position in
frame is a challenge when the arm swings about the post. Keeping an object close
to camera in frame and the distant objects in relatively the same positions is
very difficult. Dolly moves can correct for some of these problems and should
be considered but, arms on dollies need the coordination of several people with
experience.
An arm move of distant objects has little visual effect. Moving by foreground
objects close to camera or over the ground makes a much more interesting move.
Additionally, big crane moves of a foreground person in
a large empty white cyc are ineffective, as the viewer can not perceive the relative
movement as there is no information in the background.
If you don't have a remote viewfinder and have to start a shot on the ground,
you can frame up the shot on your knees, then stand up, start camera, then raise
the camera and viewfinder up where you can see and continue to operate comfortably.
Trying to stand up while shooting is difficult and will make a bad move. And as
with tripod operation, start from uncomfortable body positions to more comfortable
positions at the end of a shot.
I have to laugh at the pictures of a crane on a 3 wheel caster dolly and someone
walking along with it. If the dolly is on track there is some possibility to getting
accurate moves, but it is best if the operator can ride on the dolly.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.