Schirmer Encyclopedia of Film

Camera
Thomas Alva Edison. EVERETT COLLECTION. REPRODUCED
BY PERMISSION.
lightweight camera to film documentaries in New York
City. That same year, he created a projecting version of
his Kinetoscope, called the Vitascope.
Many features of modern motion picture cameras
were present in the Kinetograph, the Cinématographe,
and other early cameras. Both the Edison and Lumière
cameras used 35mm film, which remains the industry
standard. The Cinématographe, and eventually the
Kinetograph as well, ran at a rate of sixteen frames per
second, a rate that was used throughout the silent era.
Other elements of the camera, such as the use of a flexible
and transparent film base, an intermittent claw mechanism
to move the film forward and stop on each frame,
perforated film, and a shutter to block light in between
frames were all developed by early motion picture camera
pioneers.
ANATOMY OF A CAMERA
There are many different types of motion picture cameras
of varying sizes that serve a variety of purposes, but all
cameras have the same basic structure. The basic components
of a camera are photosensitive film, a light-proof
body, a mechanism to move the film, a lens, and a
shutter. Most cameras have a number of other features,
ranging from viewfinders to detachable magazines to
video assists, but the basic elements are the same in all
cameras (save for those of the digital variety).
The film used in modern motion picture cameras is
very much the same as the film that was developed in the
1880s and 1890s. It consists of an emulsion bound to a
flexible, transparent base. Until 1951, the base was made
of cellulose nitrate, a highly unstable substance that was
prone to fire and decay. Since the 1950s, films have used
a nonflammable safety base, usually of cellulose triacetate
(acetate) or a thinner and more durable synthetic polyester
base. Along with the emulsion, the filmstrip contains
perforations on one or both sides, used to pull the
film into place in front of the lens, and sound film has a
strip along the edge containing the soundtrack.
The film is housed in the magazine (A), a detachable,
light-tight unit that attaches to the camera.
Unexposed film starts out on the supply reel (B), and
after winding through the camera the now-exposed film
ends up on the take-up reel (C) in a separate compartment
of the magazine. There are different types of magazines
for motion picture cameras. In the most common
type, the displacement magazine, the supply reel sits
directly in front of the take-up reel in an oval-shaped
compartment on top of the camera. Coaxial magazines
mount on the back of the camera and situate the two
reels parallel to one another. Coaxial magazines are less
widely used than the displacement type, but can be useful
because their lower profile makes it possible to shoot in
smaller spaces. Quick-change magazines contain parts of
the camera mechanism in the magazine itself, making the
magazine heavier and more expensive, but allowing for
faster film changes. These magazines are generally the
rear-mounted coaxial design. Magazines hold different
amounts of film, depending on their size. Magazines for
35mm cameras most often hold 400-foot reels (four
minutes at twenty-four frames per second [fps]), 1,000foot
reels (ten minutes) or 2,000-foot reels (twenty
minutes). The standard reel size for 16mm cameras is
400 feet (eleven minutes at twenty-four fps), but other
sizes are available.
A drive mechanism, or motor, pulls the film from
the supply reel in the magazine and feeds it past the lens
and aperture. With the exception of Edison’s
Kinetograph, which used a battery-operated motor, early
cameras were cranked by hand. This practice resulted in
irregular film speeds and potentially inconsistent exposure
times, as frames were stopped in front of the lens for
varying amounts of time. The introduction of electric
motor drives meant that film could run through the
camera at a consistent pace of twenty-four frames per
second. Motor drives on modern cameras can also pro-
182 SCHIRMER ENCYCLOPEDIA OF FILM