Movie Camera and Projector: Essential Components

Posted on Dec 24, 2024 in Technology

The Essential Components of a Movie Camera

The essential components of a movie camera are:

A) The Objective

It is the camera’s optical component that carries the light to the film, forming the image in the focal plane. We will not talk more about them since they have been explained already in unit 3, but remember that you have two basic controls: focus and diaphragm.

B) The Viewfinder

It is the optical component that allows to point the camera and compose the picture. There are two types of viewers:

  1. Optical viewfinder system: It shows a similar picture but independent of what the objective catches. It has the advantage of capturing sharp images and without micro-cuts, but parallax errors may occur and complicate the use of lenses of different focal lengths and zooms.
  2. System SLR viewfinder: The image formed in the display is obtained through the lens, thus achieving it diverted some of the light from the target (using a splitter or a mirror prism semireflectant). Within reflex viewfinder systems, there are three subtypes:

2.1) Of partial mirrors: Light passing through the lens is partially diverted to the film and some toward the viewer, causing a loss of light to be compensated.

2.2) Rotating mirror: Light passing through the lens to the viewfinder is intermittently reflected by a mirror fixed to the valve itself or rotating synchronously with it, causing intermittent periods of blindness in the operator.

2.3) In video: The current film cameras carry a miniature video camera that transmits the viewfinder image to an external monitor, so the director and any other person can see the scene as viewed by the operator. This is known as video assist.

C) The Body of the Camera

It consists of the following:

  1. Print Window: A rectangular opening where the film is exposed to light that ensures the film is positioned properly to record the image. It corresponds to the film format used, but professional cameras are equipped with an interchangeable window (for the different formats in 35 mm, the use of caches, for effects, and even to be cleaned).
  2. System of the movie drag: It is the mechanism that removes the unexposed film compartment and drags your way to the window one frame at a time in an intermittent motion. Usually consists of toothed rollers that are embedded in the holes, a hook that places each frame in the print window and even a counter-hook (which gives more stability to the film) on most professional cameras. Print speed of the film is 24 fps (25 fps when shooting for TV). Lower speeds are used to accelerate the movement (including frame by frame) and higher speeds to slow it down. If a film shot to film will be issued by PAL, is made a conversion to 25 fps (at slightly reducing its duration).
  3. Shutter: A mechanism located between the lens and the print window that allows light to pass intermittently. The shutter is typically a semicircular plate with between 170 and 180 degrees of opening (providing a time exposure of 1/50 of a second) and this opening angle that determines, along with the speed (frames per second), the time period in which the film emulsion is exposed to light: the higher speed varying camera shutter opening angle, shorter exposure. The professional camera shutter is a variable shutter to adjust the opening angle as required (if the angle is reduced from 180º to 90º, the diaphragm must be opened at a stop, allowing, for example, reduce the depth field), and even allowed to do while you’re rolling (to adjust the light changes).

D) Chassis

It’s where the film is stored. Depending on its design, the movies are stored in two compartments or a single compartment in which the exposed film is occupying the place that leaves no film or expose.

E) Power System

Which consists of the engine chamber and batteries. The current cameras are equipped with a soundproofing system is not registered for the noise produced by the mechanical elements of the camera during filming.

The Essential Components of a Projector

The essential components of the projector are:

A) The Lantern

Which is the element which houses the mechanism that generates the light beam and where the projection lamp. There was formerly an electric arc to jump between two carbon electrodes, and from the 50 Xenon lamps are used (which made the passage of current through two electrodes enclosed in a capsule of gas, typically xenon). To maximize the light projection system has a concave reflector behind the lamp and a condensing lens in front of it that focuses light on the window.

B) The Objective or Objectives Tower

Located in front of the window and is responsible for the optical quality of image viewing. Various types are used (usually focal length, but also others such as anamorphic), no diaphragm and consist simply of control approach.

C) The Time Trial

Which is the gear set up to achieve the movement of the film so that each frame to remain fixed in the projection window for some time before being replaced by the next frame. Its elements are:

  1. The continuous drive system of the film: Which is achieved by means of toothed rollers that intermesh in the perforations of the film.
  2. The intermittent drive system: Which usually consist of a mechanism called the Maltese Cross. It works by using a roller trawl operated by a combination of two pieces, one of which (trading continuously) geared at regular intervals with one that features a cross. To compensate for the difference between the continuous movement of the drive roll and the Cross of Malta is left between the cross and two small loops of window film (film loops), which are stretched at the moment of maximum strain and then unfasten again. In currently manufactured electronic models (such as FP 25 E Premiere Kinoton) that are digitally controlled and no longer need such mechanisms as the Cross of Malta to achieve the intermittent movement of the film.
  3. The shutter: It works only intermittently, synchronized with the Maltese Cross or other flashing system. It has two blades and therefore the shutter frequency is 1/48 seconds: in this way reduces the scintillation screen while the form of a helix serves to ventilate the film. In small films like Super8, using a 3-blade shutter because it was common the filming (and screening) was operated at 18 fps.
  4. The projection window: In the window of exposure is insert a plate with the exhibition format.

D) The Coils

Which are those where the film is stored and where it is collected during the screening. Today’s digital projectors using DLP technology (Digital Light Processing or Digital Light Processing), developed by Texas Instruments. In DLP projectors, the image is created by microscopic mirrors arranged in a matrix on a semiconductor chip, known as Digital Micromirror Device (DMD). Each mirror represents one pixel on the projected image, so the number of mirrors corresponds to the definition of the image being filmed.