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Panoramic Photography

lens film camera cameras

The term panoramic photograph defines pictures that include a large horizontal angle of view. It is not normally associated with photographs made with conventional cameras and wide-angle lenses unless the image is cropped at the top and bottom to increase the width-to-height aspect ratio. Many single-use or other film cameras have a panoramic setting that creates a mask at the film plane to create such a ratio.

Panoramic photographs can be produced in various ways. In the era of color slide film and slide projectors, sophisticated multiple-camera systems created separate pictures that were projected side by side, resulting in a large composite image with a wide angle of view. Another panoramic system makes use of an anamorphic lens usually associated with a motion-picture camera that compresses the horizontal dimension of the scene with another anamorphic lens on the projector. The second lens re-establishes the image on the screen with a small height and large width. This is commonly called wide-screen because it requires a screen that has a greater width than required for conventional motion pictures.

Still photographers have also made panoramic photographs by panning the camera, in this case to produce a set of overlapping images that were combined into a single composite image, but this was a difficult and time-consuming process before digital photography. Panoramic photographs in the late 1980s and into the 1990s were made with panoramic cameras. A panoramic camera is a camera that is able to make a photograph with an aspect ratio greater than 1:3. Many cameras classified as panoramic cameras are simply conventional cameras fitted with a rectilinear wide-angle lens and an internal mask, which may indeed be the camera body itself. Typically these cameras do not exceed a horizontal angle of view much greater than 100 degrees. Their distinct advantage is their simplicity of operation.

On the other hand, to include greater angles of view, there are special cameras that expose scenes sequentially and are able to cover horizontal angles from about 150 to close to 360 degrees on stationary film, to over 360 degrees when the film is moved.

In each of these designs, the lens will scan the scene from side to side and expose film by projecting the image through a narrow slit in front of the film.

There were many variations of this theme. The first camera of this type was characterized by the very successful Panorama cameras manufactured by Eastman Kodak and, more recently, by the Widelux company. In these cameras, which have a limited angle of view, the film is held in a circular arc whose radius is the focal length of the lens. The lens is attached to a shaft whose axis runs through the rear nodal point of the taking lens. The lens is connected to the camera using a flexible light-tight baffle. During exposure the lens pivots about its rear nodal point, scanning the horizon from side to side while the image-forming light passes onto the film by way of a funnel-shaped fan with a slit near the film surface.

Under these conditions the lens produces a stationary image, and the exposure time is influenced by the rate at which the lens is scanned from one side to the other. Because of mechanical factors, these cameras can only cover an angle of about 150 degrees. They are, however, among the simplest of the true panoramic camera types.

A second design uses film that is held around the outside surface of a drum of radius equal to the lens focal length and within which the film supply and take-up spool are usually also stored. An outer drum, of 2× lens focal length radius, carries the lens and a light baffle that has a slit near the film surface and rotates around the inner drum. The lens has a mirror mounted in front of it to reverse image motion direction such that the image appears to stand still as far as the film is concerned. This design has never achieved any commercial success, but many amateur photographers have made prototypes that work quite successfully.

Another type of panoramic camera is the one based on a Cirkut camera, which was also made by Eastman Kodak and exemplified by such cameras as the Alpa Technorama, the Hulcherama, the Roundshot, and the Globoscope. In these designs the film and the lens both move. The lens rotates about its rear nodal point while a slit moves along a circle determined by the focal length of the lens. Simultaneously, film is transported past the slit at a speed that just matches the apparent velocity of the slit past the image, which actually is stationary. This technology is nothing more than an extension of the first type, but instead of having the film set in an arc about the lens as it pivots, the arc is built up behind the lens as the lens scans the scene. In this way, horizontal (or vertical, for that matter) angles of coverage exceeding 360 degrees are possible.

Cameras of this latter type in particular are often used for taking pictures of large groups of people. Because they are scanning cameras, the total time that it takes to make an exposure may be as long as a few seconds to more than 30 seconds, although the effective exposure time of each point in the picture may be as short as 1/10 second. Local exposure time is adjusted by varying the width of the exposing slit or the panning rate of the camera. In the case of a group shot, the subjects remain still during the exposure, as any movement leads to blurring and a compression or expansion-type distortion of a subject, depending on its direction of motion relative to the scanning direction of the camera. Double-exposure stunts are, however, possible, by one or two members located at the first extreme edge running behind the group, or around the camera, to the other edge and reaching it before the scanning shutter slit of the camera gets there.

Contemporary panoramic photography is accomplished using a digital camera and stitching software. There is an essay describing QTVR technology in the Contemporary issues section of this encyclopedia.

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