Plate
camera
The earliest cameras produced in significant numbers used sensitized
glass plates and are now termed plate cameras. Light entered a lens
mounted on a lens board which was separated from the plate by an extendible
bellows. Many of these cameras, had controls to raise or lower the lens and to
tilt it forwards or backwards to control perspective. Focusing of these plate cameras
was by the use of a ground glass screen at the point of focus. Because lens
design only allowed rather small aperture lenses, the image on the ground glass
screen was faint and most photographers had a dark cloth to cover their heads
to allow focusing and composition to be carried out more easily. When focus and
composition were satisfactory, the ground glass screen was removed and a sensitized
plate put in its place protected by a dark slide. To make the exposure, the
dark slide was carefully slid out and the shutter opened and then closed and
the dark slide replaced. In current designs the plate camera is best
represented by the view camera.
Large-format
camera
The large format camera is a direct successor of the early plate
cameras and remain in use for high quality photography and for technical,
architectural and industrial photography. There are three common types, the monorail
camera, the field camera and the press camera. All use large format sheets of
film, although there are backs for medium format 120-film available for most
systems, and have an extensible bellows with the lens and shutter mounted on a
lens plate at the front. These cameras have a wide range of movements allowing
very close control of focus and perspective.
Medium-format camera
Medium-format cameras have a film size somewhere in between the
large format cameras and the smaller 35mm cameras. Typically these systems use
120- or 220-film. The most common sizes being 6x4.5 cm, 6x6 cm and 6x7 cm.
The designs of this kind of camera show greater variation than their larger
brethren, ranging from monorail systems through the classic Hassel lad model
with separate backs, to smaller rangefinder cameras. There are even compact
amateur cameras available in this format.
Folding camera
The introduction of films enabled the existing designs for plate
cameras to be made much smaller and for the base-plate to be hinged so that it
could be folded up compressing the bellows. These designs were very compact and
small models were dubbed vest pocket cameras.
Box camera
Box cameras were introduced as a budget level camera and had few
if any controls. The original box Brownie models had a small reflex viewfinder
mounted on the top of the camera and had no aperture or focusing controls and
just a simple shutter. Later models such as the Brownie 127 had larger direct
view optical viewfinders together with a curved film path to reduce the impact
of deficiencies in the lens.
Rangefinder
camera
As
camera and lens technology developed and wide aperture lenses became more
common, range-finder cameras were introduced to make focussing more precise.
The range finder has two separated viewfinder windows, one of which is linked
to the focusing mechanisms and moved right or left as the focusing ring is
turned. The two separate images are brought together on a ground glass viewing
screen. When vertical lines in the object being photographed meet exactly in
the combined image, the object is in focus. A normal composition viewfinder is
also provided.
Single-lens
reflex
In the single-lens reflex camera the photographer sees the scene
through the camera lens. This avoids the problem of parallax which occurs when
the viewfinder or viewing lens is separated from the taking lens. Single-lens
reflex cameras have been made in several formats including 220/120 taking 8, 12
or 16 photographs on a 120 roll and twice that number of a 220 film. These correspond
to 6x9, 6x6 and 6x4.5 respectively (all dimensions in cm). Notable
manufacturers of large format SLR include Hasselblad, Mamiya, Bronica and Pentax.
However the most common format of SLRs has been 35 mm and subsequently the
migration to digital SLRs, using almost identical sized bodies and sometimes
using the same lens systems.
Almost all SLR used a front surfaced mirror in the optical path
to direct the light from the lens via a viewing screen and pentaprism to the
eyepiece. At the time of exposure the mirror flipped up out of the light path
before the shutter opened. Some early cameras experimented other methods of
providing through the lens viewing including the use of a semi transparent pellicle
as in the Canon Pellix and others with a small periscope such
as in the Corfield Periflex series.
Twin-lens reflex
Twin-lens reflex cameras used a pair of nearly identical lenses,
one to form the image and one as a viewfinder. The lenses were arranged with
the viewing lens immediately above the taking lens. The viewing lens projects
an image onto a viewing screen which can be seen from above. Some manufacturers
such as Mamiya also provided a reflex head to attach to the viewing screen to
allow the camera to be held to the eye when in use. The advantage of a TLR was
that it could be easily focussed using the viewing screen and that under most
circumstances the view seen in the viewing screen was identical to that
recorded on film. At close distances however, parallax errors were encountered
and some cameras also included an indicator to show what part of the
composition would be excluded.
Some TLR had interchangeable lenses but as these had to be
paired lenses they were relatively heavy and did not provide the range of focal
lengths that the SLR could support. Although most TLRs used 120 or 220 film
some used 127 film.
Ciné
camera
A ciné camera or movie camera takes a rapid sequence of
photographs on strips of film. In contrast to a still camera, which captures a
single snapshot at a time, the ciné camera takes a series of images, each
called a "frame" through the use of an intermittent mechanism.
The frames are later played back in a ciné projector at a
specific speed, called the "frame rate" (number of frames per
second). While viewing, a person's eyes and brain merge the separate pictures
to create the illusion of motion. The first ciné camera was built around 1888
and by 1890 several types were being manufactured. The standard film size for
ciné cameras was quickly established as 35mm film and this remains in use to
this day. Other professional standard formats include 70 mm film and 16mm film
whilst amateurs film makers used 9.5 mm film, 8mm film or Standard 8 and Super
8 before the move into digital format.
The size and complexity of ciné cameras varies greatly depending
on the uses required of the camera. Some professional equipment is very large
and too heavy to be hand held whilst some amateur cameras were designed to be
very small and light for single-handed operation. In the last quarter of the
20th century camcorders supplanted film motion cameras for amateurs. Professional
video cameras did the same for professional users around the turn of the
century.
