Movie camera having adjustable shutter
AssigneePanavision, Inc.
InventorsBrian C. Dang, Albert K. Saiki, Eric M. Chang
Life of this patent
Estimating the term…
Abstract
A shutter system for a movie camera or the like for controlling the film exposure including a main shutter wheel rotatably mounted on main drive shaft driven by a first motor and at least one adjustable shutter wheel positioned adjacent to and coaxially rotating with the main shutter wheel, the adjustable shutter wheel being mounted on a secondary shaft independently driven by a second motor. Both the aperture (determined by the relative positions of the shutter wheels of the main shutter wheel and adjustable shutter wheel) and the shutter speed are set by a controller which regulates the speed of each of the motors.
Claims25
A motion picture camera system comprising:
- a camera housing;
- a film advance mechanism for advancing film past a shutter opening;
- a shutter mechanism, comprising:
- a main shaft rotatably mounted to rotate about a first axis,
- a main shutter wheel mounted to the main shaft and having at least one radially extending main shutter element forming at least one arcuate aperture,
- a secondary shaft rotatably mounted to rotate about the first axis,
- a first adjustable shutter wheel mounted to the secondary shaft and positioned adjacent said main shutter wheel, said first adjustable shutter wheel having a same number of radially extending shutter members as the radially extending main shutter elements,
- a main shutter motor mounted on the housing, the main shutter motor being connected to and driving the main shaft,
- a secondary shutter motor mounted on the housing, the secondary shutter motor being connected to and driving the secondary shaft;
- a third shaft;
- a second adjustable shutter mounted on the third shaft;
- and
- a third motor for rotating the third shaft;
- and
- means for adjusting position of the first adjustable shutter wheel relative to the main shutter wheel for controlling speed of at least one of the secondary shutter motor and the main shutter motor.
A method for exposing film in a movie camera comprising the steps of:
- passing light through a lens opening onto the film;
- positioning a main shutter wheel between the lens opening and the film for alternately interrupting and passing the light from the lens to the film by rotating the main shutter wheel having a radial element with a first motor to interrupt the light and an aperture for passing the light;
- moving the film past the lens opening during interruption of the light;
- positioning at least a first adjustable shutter wheel, having radially extending members, coaxially with and adjacent to the main shutter wheel;
- rotating the first adjustable shutter wheel with a second motor at a same speed as that of the first motor;
- and
- controlling exposure of the film by closing off portions of the apertures between said main shutter elements by moving said radially extending members of the adjustable shutter wheel members into the aperture,
- wherein the step of controlling exposure comprises:
- positioning a second adjustable shutter wheel, having radially extending members, coaxially with and adjacent to the main shutter wheel between the main shutter wheel and the first adjustable shutter wheel;
- rotating the second adjustable shutter wheel to rotate at the same speed as the first adjustable shutter wheel;
- adjusting relative angular position of the first and the second adjustable shutter wheels relative to the main shutter wheel so as to close off portions of the aperture, the first and second adjustable shutter wheels being adjusted in opposite directions about the aperture,
- wherein the second adjustable shutter is rotated by a third motor.
Dependencies are inferred from the claim text.