Panoramic photography

Panoramic photography is a format of photography that aims to create images with exceptionally wide fields of view, but has also come to refer to any photograph that is cropped to a relatively wide aspect ratio ("see Panoramic format") While there is no formal definition for the point at which "wide-angle" leaves off and "panoramic" begins, truly panoramic image are thought to capture a field of view comparable to, or greater than, that of the human eye - about 160° by 75° - and should do so while maintaining detail across the entire picture. The resulting images are "panoramic", in that they offer an unobstructed or complete view of an area - often, but not necessarily, taking the form of a wide strip. A panoramic photograph is really defined by whether the image gives the viewer the appearance of a "panorama," regardless of any arbitrary technical definition.

Photo-finishers and manufacturers of Advanced Photo System (APS) cameras also use the word "panoramic" to refer to any print format with a wide aspect ratio, not necessarily photos that encompass a large field of view. In fact, a typical APS camera in its panoramic mode, where its zoom lens is at its shortest focal length of around 24 mm, has a field of view of only 65°, which many photographers would only classify as wide angle, not panoramic. Cameras with an aspect ratio of 2:1 or greater (where the width is 2 times its height) can generally be classified as being "panoramic."

History

Panoramic photography has a history almost as old as photography itself. One of the first recorded patents for a panoramic camera was submitted by Joseph Puchberger in Austria in 1843 for a hand-cranked, 150° field of view, 8-inch focal length camera that exposed a relatively large Daguerreotype, up to convert|24|in|mm long. A more successful and technically superior panoramic camera was assembled the next year by Friedrich von Martens in Germany in 1844. His camera, the Megaskop, added the crucial feature of set gears which offered a relatively steady panning speed. This in turn properly exposed the photographic plate, as unsteady speeds can create an unevenness in exposure, called "banding". [Martens did not invent in Germany but rather Paris, France, where he was employed by Lerebours, photographer/publisher. It is also possible that Martens camera was perfected before Puchberger patented his camera] . Because of the high cost of materials and the technical difficulty of properly exposing the plates, Daguerreotype panoramas, especially those pieced together from several plates (see below) are rare.

After the advent of wet-plate colloidian process photographers would take anywhere from 2 to a dozen of the ensuing albumen prints and piece them together to form a panoramic image ("see: Segmented"). As one might assume, this photographic process was technically easier and far less expensive than Daguerreotypes. Some of the most famous early panoramas were assembled this way by George Barnard, a photographer for the Union Army in the American Civil War in the 1860s. His work provided vast overviews of fortifications and terrain, much valued by engineers, generals, and artists alike. ("see Photography and photographers of the American Civil War")

Following the invention of flexible film in 1888 panoramic photography was revolutionized. The invention, initially created by Hannibal Goodwin and later copied and marketed by the Eastman Kodak Company, was a milestone in photography and greatly benefited panoramic photography in particular, spawning a wave of cameras utilizing this new, convenient, and practical method. Soon after dozens of cameras came on the market, many with brand names heavily indicative of their time. Cameras such as the Cylindrograph, Cyclograph, Cycloramic, Wonder Panoramic, Pantascopic, Multiscope, Cyclorama, Panomax, Veriwide, Wiscawide, Ultrawide, Cyclo-Pan, Fuji 617, Art Panorama 624 and 617, Tomiyama 617, Noblex 617, Roundshot 35 mm & 70 mm, Widelux, Technorama, Hulcherama, Tecnorama, Globoscope, Al-Vista, Cyclops Wide-Eye [http://www.gaspweb.co.uk/cameras/cyclops.html] , the I-Pan, V-Pan, Hasselblad X-Pan, and Z-pan are just a few examples of the many panoramic cameras that flooded the market in the subsequent century.

One of the most interesting, and most fallible, panoramic cameras created during this period was the Doppel-Sport Panoramic Camera. Created in 1912 by Dr. Julius Neubronner in Kronberg, Germany, the camera was carried by a pigeon. A delayed shutter on the camera was set, the pigeon released, and small photograph was taken. There is no record that Neubronner ever recovered a camera.

Panoramic cameras and methods

hort rotation (or swing-lens)

"Short rotation" is a term used to define cameras that have a lens that rotates around the camera's rear nodal point (the optical point from which the focal length is measured) opposite a curved film plane.cite paper|title=Theory of the “No-Parallax” Point in Panorama Photography | url=http://www.janrik.net/PanoPostings/NoParallaxPoint/TheoryOfTheNoParallaxPoint.pdf | author=Littlefield, Rik | version=ver. 1.0 | date=2006-02-06 | format=pdf | accessdate=2007-01-14] As the photograph is taken, the lens pivots around its nodal point while, at the same time, a slit exposes the vertical strip of film that is aligned with the axis of the lens. The entire exposure usually takes only a fraction of a second and the camera's function is similar to that of viewing a scene by turning your head from side to side on a steady level. Also referred to as "rotating lens" or "swing lens", this method often encompasses a very wide angle of view, similar to that of the fisheye lens, but without the extreme distortion of lines which is often seen in extreme wide-angle lenses. Typically, these cameras offer a field of view between 110° to 140° and an aspect ratio of 2:1 to 4:1. The images produced commonly take up 1.5 to 3 times as much space on the negative as the exposure made by traditional 35 mm cameras. For instance, the traditional dimensions of an exposure on 35 mm film is 36x24 mm, while the dimensions produced from a short rotation camera with a 140° field of view would be approximately 58x24 mm. Therefore rolls of 24-exposure film would only yield around 18 exposures. Notable cameras of this type include the Widelux, Noblex, and the Horizon. The more obscure Russian "Spaceview FT-2", originally an artillery spotting camera, took 12 shots on 39-exposure 35 mm film.

Unfortunately, short rotation cameras have a number of limitations. They usually only offer a relatively small amount of shutter speeds and have poor focusing ability, with most models having a fixed focus, set to the hyperfocal distance of the maximum aperture of the lens. This is often as far away as 10 meters (30 ft) or more. To compensate for this, panoramic photographers desiring to shoot a subject in a closer range must use a small aperture to bring the foreground into focus, limiting the camera's use in low-light situations. For these reasons, cameras of this type are most often used outside, specifically for landscape or kite photography, where there is usually plenty of available light and there is less requirement for short focusing depths.

Rotating lens cameras also produce a notable and odd "distortion" of lines. If the horizon, for instance, is placed even slightly off-center, the horizon line will bow slightly in the opposite direction. While this 'distortion' is in fact accurate and correct, it nevertheless looks unusual to the viewer. This is chiefly because the image, which was originally viewed and captured from a sweeping, curved perspective, is now viewed flat. To truly view the resulting image correctly, the viewer would have to produce a sufficiently large print and curve it identically to the curve of the film plane in the camera. Now, with the viewer panning their view, they can view the image most accurately. This type of 'distortion' can be reduced by using a swing-lens camera with a 'normal' focal length lens [the FT-2 has a 50 mm while most other 35 mm swing lens cameras use a wide-angle lens] , and by photographing buildings from a corner location, not from the center of a flat surface.

Swing lens panoramic cameras have also been built --in small to very large sizes-- for use while suspended by kites [or helicopters, in the modern era] .

Full rotation

"Rotating panoramic cameras" (also referred to as "slit scan" or "scanning cameras") are cameras that are similar to the swing-lens (or short rotation) cameras, but are capable of 360° of rotation or more, because the whole camera rotates, not just the lens. A clockwork or motorized mechanism rotates the camera continuously and evenly and simultaneously pulls the film through the camera, in such a way that the speed of the film matches the speed with which the image moves across the image plane. Exposure is made through a narrow slit. Using only the central part of the image field produces a very sharp picture whose characteristics are very even from edge to edge. Historically, these cameras were, and still are, widely used for group pictures, particularly of athletic teams. Today, a digital rotating line camera also composes a full 360° panorama, line by line, where a linear sensor may have (for example) 10,000 sensor elements (e.g., produced in charge-coupled device technology), and a full 360° panorama may be composed in this case of about 120,000 individual `line images'. A resulting image is then (for this example) in the order of 1,200 Megapixel. Digital rotating line cameras are, for example, used for documenting historic buildings or sites. Notable digital cameras include the Panoscan and Eyescan.

Notable (non-digital) cameras include the Cirkut, Hulcherama, Leme, Roundshot and Globuscope, all of which are capable of 360° of rotation.

Panoramic Photography is commonly used in theater to capture a picture of the entire cast. Many times, as a tradition, the cast will have a "runner" who will appear on both sides of the photograph by running to the other after the camera has moved past them.

Fixed lens

"Fixed lens" cameras (also known as "flatback" and "wide view" or "wide field") are essentially panoramic cameras that have fixed, stationary lenses and a flat film plane - as opposed to the rotating lenses and curved film planes of short rotation panoramic cameras. These are the most common form of panoramic camera and range from relatively poor quality and inexpensive APS cameras, right up to the professional 6x17 and 6x24 cm medium format variety. Larger panoramic cameras using sheet film have been made and are available in formats up to 10x24 inches. The key difference between an APS or 35 mm camera's simply crop the normal frame into a panoramic aspect ratio, thereby losing a significant portion of the film area, while professional 35 mm or medium format fixed lens panoramic cameras make use of the entire height of the film and have an extended film plane, giving higher resolution images. Another key benefit is that, due to the fact that these types of camera expose the film in a single instantaneously exposure like traditional cameras as opposed to the longer, sweeping exposure of other types of panoramic cameras, fixed lens cameras can make use of a flash. Flashes would not work consistently with rotational panoramic cameras because the flash, which usually are around 1/1000 of a second, would only be captured on the part of the image that is being exposed when the flash goes off, not the entire image. In addition to this benefit, these cameras do not cause linear objects to curve, making them the panoramic camera of choice for architectural photography.

With a flat film plane, 90° is about the widest field of view that can be captured with normal sharpness and without significant wide-angle distortion or light fall off by a traditional lens and camera using a single, flat piece of film. Lenses with up to 120 degrees angle of view are available, but require a center filter to correct for light fall off toward the edge of the image. Lenses that capture wider angles—up to 180° —exist, but are commonly known as fisheye lenses and exhibit extreme geometrical distortion but typically less brightness falloff at the edges than normal (rectilinear) lenses.

Notable cameras are the 35 mm Hasselblad X-Pan and the medium format Linhof 612PC, Horseman SW612, Linhof Technorama 617, Tomiyama Art Panorama 617 and 624, and Fuji G617 and GX617.

More recently, a company named ImmerVision has created the new panomorph lens. This lens provides a full hemispheric field of view with no blind zone, different from catadioptric lenses that cause a blind spot in the middle of the image.

egmented

Segmented panoramas, also referred to as "stitched" panoramas, are made by joining multiple conventional photographs with slightly overlapping fields of view so as to create a larger, panoramic image once assembled. Without computers, countless amateur and professional photographers attempted to create panoramic views in this way and found that the craftsmanship needed to match the images and hide the seams was all but unattainable. However, modern digital workflows use stitching software to combine multiple images, which is probably the most common technique for creating panoramic images today. In order to correctly stitch images together without parallax error, the camera needs to be rotated about the center of its entrance pupil.cite paper|title=Theory of the “No-Parallax” Point in Panorama Photography | url=http://www.janrik.net/PanoPostings/NoParallaxPoint/TheoryOfTheNoParallaxPoint.pdf | author=Littlefield, Rik | version=ver. 1.0 | date=2006-02-06 | format=pdf | accessdate=2007-01-14] [cite web | author=Kerr, Douglas A. | year=2005 | title=The Proper Pivot Point for Panoramic Photography | format=PDF | work=The Pumpkin | url=http://doug.kerr.home.att.net/pumpkin/Pivot_Point.pdf | accessdate=2007-01-14] [cite web | author=van Walree, Paul | title=Misconceptions in photographic optics | url=http://www.vanwalree.com/optics/misconceptions.html#m6 | accessdate=2007-01-14 Item #6.]

Catadioptric Cameras

A recent development in panoramic and wide field of view imaging has been the commercialization of lens and mirror based (catadioptric) systems. These imaging systems (cameras) consisist of off the shelf lenses and curved mirrors that reflect the complete 360 degree panoramic field of view into the lens based optics. The image acquired usually looks unlike typical panoramas (spherical or cylindrical). However, the mirror shape and lens used is specifically chosen and arranged such that the effective camera maintains a single viewpoint. The single viewpoint means the complete panorama is effectively imaged or viewed from a single point in space. Thus, one can simply warp the acquired image into a cylindrical or spherical panorama. Even perspective views of smaller fields of view can be accurately computed.

The biggest advantage of catadioptric systems is that because one uses mirrors to bend the light rays instead of lenses (like fish eye), the image has almost no chromatic aberrations or distortions. Moreover, since the complete panorama is imaged at one shot, dynamic scenes can be captured without problems. In fact panoramic video can be captured and has found applications in robotics and journalism.

ee also

*Panoramic Tripod Heads
*
*Panorama Tools (software)
*Hugin (software)
*PTgui
*CleVR
*Panoscan
*QTVR is a format that can be used to display panoramas

Notes and references

*cite book | author=Meers, Nick | title=Stretch: The World of Panoramic Photography | publisher=Rotovision | year=2003 | id=ISBN 2-88046-692-X

External links

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* [http://www1.cs.columbia.edu/CAVE/projects/cat_cam_360/cat_cam_360.php Catadioptric Imaging at Columbia University]
* [http://www.panoramicassociation.org Panoramic Association] A world-wide organization devoted to educating the public on and showcasing the work of panoramic photographers.
* [http://www.panoramicphoto.com/timeline.htm A timeline of panoramic cameras 1843-1994]