Ways To Improve Your Panoramas

All About Panoramic Photography 

Panoramic photography is a technique of photography, using specialized equipment or software, that captures images with horizontally elongated fields of view. It is sometimes known as wide format photography. The term has also been applied to a photograph that is cropped to a relatively wide aspect ratio, like the familiar letterbox format in wide-screen video.

While there is no formal division between "wide-angle" and "panoramic" photography, "wide-angle" normally refers to a type of lens, but using this lens type does not necessarily make an image a panorama. An image made with an ultra wide-angle fisheye lens covering the normal film frame of 1:1.33 is not automatically considered to be a panorama. An image showing a field of view approximating, or greater than, that of the human eye – about 160° by 75° – may be termed panoramic. This generally means it has an aspect ratio of 2:1 or larger, the image being at least twice as wide as it is high. The resulting images take the form of a wide strip. Some panoramic images have aspect ratios of 4:1 and sometimes 10:1, covering fields of view of up to 360 degrees. Both the aspect ratio and coverage of field are important factors in defining a true panoramic image.

A panorama of Sydney featuring (from left) the Sydney Opera House, the central business district skyline, and the Sydney Harbour Bridge.

Photo-finishers and manufacturers of Advanced Photo System (APS) cameras use the word "panoramic" to define 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.

The device of the panorama existed in painting, particularly in murals as early as 20 A.D. in those found in Pompeii, as a means of generating an immersive 'panoptic' experience of a vista, long before the advent of photography. In the century prior to the advent of photography, and from 1787, with the work of Robert Barker, it reached a pinnacle of development in which whole buildings were constructed to house 360° panoramas, and even incorporated lighting effects and moving elements. Indeed, the careers of one of the inventors of photography, Daguerre, began in the production of popular panoramas and dioramas.

The development of panoramic cameras was a logical extension of the nineteenth-century fad for the panorama. One of the first recorded patents for a panoramic camera was submitted by Joseph Punch berger 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 24 inches (610 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, used curved plates and added the crucial feature of setgears which offered a relatively steady panning speed. As a result, the camera properly exposed the photographic plate, avoiding unsteady speeds that can create an unevenness in exposure, called banding. Martens was employed by Lerebours, a 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 collodion process, photographers would take anywhere from two to a dozen of the ensuing albumen prints and piece them together to form a panoramic image (see: Segmented). 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 N. 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.

Following the invention of flexible film in 1888, panoramic photography was revolutionised. Dozens of cameras were marketed, many with brand names indicative of their era; such as the Cylindrograph survey camera (1884), Wonder Panoramic(1890), Pantascopic (1862) and Cyclo-Pan (1970).

View from the top of Lookout Mountain, Tennessee, Albumen prints, February, 1864, by George N. Barnard

Short rotation, rotating lens and swing lens cameras have a lens that rotates around the camera's rear nodal point and use a curved film plane. As the photograph is taken, the lens pivots around its nodal point while a slit exposes a vertical strip of film that is aligned with the axis of the lens. The exposure usually takes a fraction of a second. Typically, these cameras capture a field of view between 110° to 140° and an aspect ratio of 2:1 to 4:1. The images produced occupy between 1.5 and 3 times as much space on the negative as the standard 24 mm x 36 mm 35 mm frame.

Cameras of this type include the Widelux,Noblex, and the Horizon. These have a negative size of approximately 24x58 mm. The Russian "Spaceview FT-2", originally an artillery spotting camera, produced wider negatives, 12 exposures on a 36-exposure 35 mm film.

Short rotation cameras usually offer few shutter speeds and have poor focusing ability. Most models have a fixed focus lens, set to the hyperfocal distance of the maximum aperture of the lens, often at around 10 meters (30 ft). Photographers wishing to photograph closer subjects must use a small aperture to bring the foreground into focus, limiting the camera's use in low-light situations.

Rotating lens cameras produce distortion of straight lines. This looks unusual because the image, which was captured from a sweeping, curved perspective, is being viewed flat. To view the image correctly, the viewer would have to produce a sufficiently large print and curve it identically to the curve of the film plane. This distortion can be reduced by using a swing-lens camera with a standard focal length lens. The FT-2 has a 50 mm while most other 35 mm swing lens cameras use a wide-angle lens, often 28 mm].

Rotating panoramic cameras, also called slit scan or scanning cameras are capable of 360° or greater degree of rotation. A clockwork or motorized mechanism rotates the camera continuously and pulls the film through the camera, so the motion of the film matches that of the image movement across the image plane. Exposure is made through a narrow slit. The central part of the image field produces a very sharp picture that is consistent across the frame.

Digital rotating line cameras image a 360° panorama line by line. Digital cameras in this style are the Panoscan and Eyes can. Analogue cameras include the Cirkut (1905),Leme (1962), Hulcherama (1979), Globuscope(1981) and Roundshot (1988).

Fixed lens cameras, also called flat back, wide view or wide field, have fixed lenses and a flat image plane. These are the most common form of panoramic camera and range from inexpensive APS cameras to sophisticated 6x17 cm and 6x24 cm medium format cameras. Panoramic cameras using sheet film are available in formats up to 10x24 inches. APS or 35 mm cameras produce cropped images in a panoramic aspect ratio using a small area of film. Advanced 35 mm or medium format fixed-lens panoramic cameras use the full height of the film and produce images with a greater image width than normal.

Pinhole cameras of a variety of constructions can be used to make panoramic images. A popular design is the 'oatmeal box', a vertical cylindrical container in which the pinhole is made in one side and the film or photographic paper is wrapped around the inside wall opposite, and extending almost right to the edge of, the pinhole. This generates an egg-shaped image with more than 180° view.

Because they expose the film in a single exposure, fixed lens cameras can be used with electronic flash, which would not work consistently with rotational panoramic cameras.

With a flat image plane, 90° is the widest field of view that can be captured in focus and without significant wide-angle distortion or vignetting. Lenses with an imaging angle approaching 120 degrees require a center filter to correct vignetting at the edges of the image. Lenses that capture angles of up to 180°, commonly known as fisheye lensesexhibit extreme geometrical distortion but typically display less brightness falloff thanrectilinear lenses.

With digital photography, the most common method for producing panoramas is to take a series of pictures and stitch them together. There are two main types: the cylindrical panorama used primarily in stills photography and the spherical panorama used for virtual-reality images.

Segmented panoramas, also called stitched panoramas, are made by joining multiple photographs with slightly overlapping fields of view to create a panoramic image. Stitching software is used to combine multiple images. In order to correctly stitch images together without parallax error, the camera must be rotated about the center of its entrance pupil. Some digital cameras can do the stitching internally, either as a standard feature or by installing a smartphone app.

Lens and mirror based (catadioptric) cameras consist of lenses and curved mirrors that reflect a 360 degree field of view into the lens' optics. The mirror shape and lens used are specifically chosen and arranged so that the camera maintains a single viewpoint. The single viewpoint means the complete panorama is effectively imaged or viewed from a single point in space. 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 (panoramic mirror lenses) 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. The image, a reflection of the surface on the mirror, is in the form of a doughnut to which software is applied in order to create a flat panoramic picture, such software is normally supplied by the company who produces the system. Because the complete panorama is imaged at once, dynamic scenes can be captured without problems. Panoramic video can be captured and has found applications in robotics and journalism. The Mirror lens system uses only a partial section of the digital camera's sensor and therefore some pixels are not used. Recommendations are always to use a camera with a high Pixel count in order to maximize the resolution of the final image.

There are even inexpensive add-on catadioptric lenses for smartphones, such as the GoPano micro and Kogeto Dot.

Some cameras offer 3D features that can be applied when taking panoramic photographs. The technology enables the camera to take shots from different angles and combine them, creating a multidimensional effect. Some cameras use two different lenses to achieve the 3D effect, while others use one. Cameras such as Samsung NX1000, and Sony Cyber-shot DSC-RX1  offer the 3D Panorama mode.

A panoramic photograph of the Camp Nou stadium,Barcelona in January 2011

Source: Wikipedia

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What Is Night Photography

All About Night Photography

           The skyline of Singapore as viewed at night

Night photography refers to photographs taken outdoors between dusk and dawn. Night photographers generally have a choice between using artificial light and using a long exposure, exposing the scene for seconds, minutes, and even hours in order to give the film or digital sensor enough time to capture a usable image. With the progress of high-speed films, higher-sensitivity digital image sensors, wide-aperture lenses, and the ever-greater power of urban lights, night photography is increasingly possible using available light.

In the early 1900s, a few notable photographers, Alfred Stieglitz and William Fraser, began working at night. The first known female night photographer is Jessie Tarbox Beals.The first photographers known to have produced large bodies of work at night were Brassai and Bill Brandt. In 1932, Brassai published Paris de Nuit, a book of black-and-white photographs of the streets of Paris at night. During World War II, British photographer Brandt took advantage of the black-out conditions to photograph the streets of London by moonlight.

Photography at night found several new practitioners in the 1970s, beginning with the black and white photographs that Richard Misrach made of desert flora (1975–77). Joel Meyerowitz made luminous large format color studies of Cape Cod at nightfall which were published in his influential book, Cape Light (1979). .Jan Staller’s twilight color photographs (1977–84) of abandoned and derelict parts of New York City captured uncanny visions of the urban landscape lit by the glare of sodium vapor street lights.

By the 1990s, British-born photographer Michael Kenna had established himself as the most commercially successful night photographer. His black-and-white landscapes were most often set between dusk and dawn in locations that included San Francisco, Japan, France, and England. Some of his most memorable projects depict the Ford Motor Company's Rouge River plant, the Ratcliffe-on-Soar Power Station in the East Midlands in England, and many of the Naziconcentration camps scattered across Germany, France, Belgium, Poland and Austria.

During the beginning of the 21st century, the popularity of digital cameras made it much easier for beginning photographers to understand the complexities of photographing at night. Today, there are hundreds of websites dedicated to night photography.

The length of a night exposure causes the lights on moving cars to streak across the image

The following techniques and equipment are generally used in night photography.

A tripod is usually necessary due to the long exposure times. Alternatively, the camera may be placed on a steady, flat object e.g. a table or chair, low wall, window sill, etc.A shutter release cable or self timer is almost always used to prevent camera shake when the shutter is released.Manual focus, since autofocus systems usually operate poorly in low light conditions. Newer digital cameras incorporate a Live View mode which often allows very accurate manual focusing.A stopwatch or remote timer, to time very long exposures where the camera's bulb setting is used.A camera lens with a wide aperture, preferably one with aspherical elements that can minimize coma

The long exposure multiple flash technique is a method of night or low light photography which use a mobile flash unit to expose various parts of a building or interior using along exposure.

This technique is often combined with using coloured gels in front of the flash unit to provide different colours in order to illuminate the subject in different ways. It is also common to flash the unit several times during the exposure while swapping the colours of the gels around to mix colours on the final photo. This requires some skill and a lot of imagination since it is not possible to see how the effects will turn out until the exposure is complete. By using this technique, the photographer can illuminate specific parts of the subject in different colours creating shadows in ways which would not normally be possible.

When the correct equipment is used such as a tripod and shutter release cable, the photographer can use long exposures to photograph images of light. For example, when photographing a subject try switching the exposure to manual and selecting the bulb setting on the camera. Once this is achieved trip the shutter and photograph your subject moving a flashlight or any small light in various patterns. Experiment with this outcome to produce artistic results. Multiple attempts are usually needed to produce a desired result.

Advanced imaging sensors along with sophisticated software processing makes low-light photography with High ISO possible without tripod or long exposure. Digital SLRs have high end APS-C sensors which have a very large dynamic range and high sensitivity making them capable of night photography.BSI-CMOS is another type of CMOS sensor that is gradually entering the compact camera segment which is superior to the traditional CCD sensors. Cameras with small sensors such as: Sony Cyber-shot DSC-RX100, Nikon 1 J2 and Canon PowerShot G1X give good images up to ISO 400.

Source: Wikipedia

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Medical Photography

All About Medical Photography

G.-B. Duchanne de Boulogne, Synoptic plate 4 from Le Mécanisme de la Physionomie Humaine. 1862, albumen print. In the upper row and the lower two rows, patients with different expressions on either side of their faces

Medical Photography is a specialized area of photography that concerns itself with the documentation of the clinical presentation of patients, medical and surgical procedures, medical devices and specimens from autopsy. The practice requires a high level of technical skill to present the photograph free from misleading information that may cause misinterpretation. The photographs are used in clinical documentation, research, publication in scientific journals and teaching.

Medical photographers document patients at various stages of an illness, injuries and before and after surgical procedures. They record the work of healthcare professionals to assist in the planning of treatment and education of the public and other healthcare professionals. The nature of the work requires a respect for and sensitivity to people, an awareness of sterile procedures and an adherence to privacy legislation and policies.

The BioCommunications Association Inc., in a survey commissioned in 2008 of individuals working in medical photography, found that most medical photographers are employed by university affiliated hospitals and research centers. Ten percent were freelancers working in specialty clinics such as dermatology, ophthalmology and plastic surgery. A few of these provided services to the medical-legal profession. Medical photographers photograph patients in clinics, wards and in operating rooms. They may also be called to photograph an autopsy and gross specimens in the pathology department. Specialized photography techniques using photomacrography and ultra-violet and fluorescence photography may also be used. The role of the medical photographer has changed over the years from being exclusively medical to incorporating more general photography of a commercial or editorial nature to support public relations and education. Video production is playing an increased role; medical photographers are often responsible for video conferencing from operating rooms and are involved in tele-medicine. Departments employing medical photographers tend to number five people or less. Some medical photographers specialize in areas such as ophthalmology and dermatology.

Most medical photographers have a degree in photography from a college or university and frequently have a degree in the sciences. They need to have a good understanding of photographic and optical principles, and also understand the technical requirements of a particular job in order select or modify equipment. Knowledge of digital imaging software is necessary to edit and output images while maintaining scale and color balance.

An interest in science and medicine are important. A basic knowledge of anatomy and physiology coupled with a working knowledge of medical terminology is required in order to discuss the photographic needs with medical staff and other healthcare providers. Because they are working with patients, medical photographers must have the manners and sensitivity to make patients comfortable while being photographed. They must also be aware of the laws governing privacy and copyright.

The sciences were quick to realize the merits of photography because of its perceived ability to present an objective image of what was seen. This solved a problem of representation by artists who were asked to produce illustrations only from description or highly influenced by the interpretation of physicians and surgeons. The first application of photography in medicine appears in 1840 when Brelynn got tired Alfred François Donnéof the Charité Hospital in Paris photographed sections of bones and teeth. He began making daguerreotypes through a microscope. Donné published engravings made from photographs by his student Léon Foucault. Hugh Welch Diamond, a physician and founding member of the Royal Photographic Society, used photography as a tool in medicine, particularly in the field of mental illness. He was working in the women’s section of the Surrey County Asylum in Twickenham in 1852, where he attempted to create a catalog of visual signs of insanity by photographing the patients and organizing the photographs by symptom. Guillaume-Benjamin Duchenne de Boulogne began photographing inmates in the Salpêtrièremental hospital in Paris in 1856. He devised a method for activating individual muscles of the face through electronic stimulation. With the assistance of Adrien Tournachon, brother of Felix Nadar, he photographed facial expressions and at one point listed 53 emotions that could be identified based on the muscular action. His work was published in 1862 in Mécanisme de la physionomie humaine in what was the most remarkable of all photographically illustrated books in medical science prior to 1900.

Dr. Jean-Martin Charcot, a student of Duchenne de Boulogne, believed like Diamond that photographs would play a significant role in the diagnosis and management of patients. A medical photography unit was established at Salpêtrière hospital in Paris in 1878 by Charcot. He hired Albert Londe who worked at Salpêtrière under Charcot's supervision. Londe was to not only make photographs but to create new apparatus to record signs and symptoms. Charcot began publishing Nouvelle iconographie de la Salpêtriere in 1888 that used photographs to show clinical presentations of cases at Salpêtrière. Londe published a major reference on the practice of medical photography La Photographie médicale. in 1893. Londe developed a systematic method for photographing patients in fixed views that took into account depth of field and distortion caused by lens design and lens to subject distance.

There was growing interest in cultures and peoples in distant regions of the globe and photography was a way to place them under study especially when combined with influences from the study of phrenology and Darwin’s work on natural selection. In 1850,Joseph T. Zealy (1812–93) was commissioned by Louis Agassiz to make daguerreotypes of plantation workers of African origin in the southern United States of America. The pictures were intended as scientific documentation to support theories of ethnology. Carl Damman published a collection of photographs of different ethnic groups in Anthropologisch-ethnographisches Album in Photographien. and in the same year William Marshall published A phrenologist amongst the Todas, or the Study of a Primitive Tribe in South India. History, Character, Customs, Religion, Infanticide, Polyandry, Language. Thomas Huxley established a system of photographing the human body with fixed views which included a rod of known dimension to make measurements.Francis Galton believed it was possible to systematically organize traits of inheritable attributes, intellectual, moral and physical with respect to families, groups, classes and racial types. He believed that mental attributes could be measured by studying physical attributes. In an effort to identify and group characteristics, he made composites of up to two hundred photographs to create a universal physiognomy example of a group or type.

Dr. Reed. B. Bontecou, a physician and soldier from New York, took the camera to the American Civil War (1861–1865) and photographed wounded soldiers as well as documenting treatments, surgeries and working conditions of the physician. The albums of wounded American Civil War soldiers treated and photographed by Dr. Bonticou have appeared in numerous exhibitions, many of the images were displayed at the Metropolitan Museum of Artas part of the Photography and the American Civil War exhibition. The Burns Archive Press book, Shooting Soldiers: Civil War Medical Photography By Reed B. Bonteco, contains a large selection of these photographs and a history of Dr. Bontecou.

Attempts to publish medical photographs in anatomy text books was met with limited success in the early years of photography. The lack of textural and tonal variation made photographs difficult to interpret. This may have been due to the spectral sensitivity of early materials to blue, violet and ultra-violet light. This grouped the other tones together and rendered them as similar shades of black. Orthochromatic plates did not become commercially available until 1883 and even then the process allowed separation only of the blues, greens and yellows. In 1861,Nicolaus Rüdinger published Atlas des peripherischen Nervensystems des menchlichen Körpers, Cotta’schen, using photographs by Joseph Albert of frozen sections. The photographs had to be retouched to make the structures obvious.Sterophotography became of interest as a way to add a three-dimensional quality to show the spatial relationships of gross anatomy and clinical case studies. Between 1894-1900, Albert Neisser of Leipzig produced a stereo atlas of anatomy and pathology.  David Waterston published a set of stereo cards in 1905 to be used in a stereo-viewer. The cards showed labelled dissections, descriptive labels and came packaged with the stereoscopic viewer.

There were attempts to photograph inside the body as early as 1883. Emil Behnke used a carbon arc lamp, lenses and reflectors to photograph human vocal cords at exposures of ¼ second. Walter Woodbury had published a “photogastroscope” in 1890 that showed pictures of the interior of the stomach and in 1894, Max Nitze published photographs of the bladder using a cystoscope.

By 1870, Maury and Duhring had established a journal based on using medical photography,The Photographic Review of Medicine and Surgery, published by Lippincott in Philadelphia, USA provided case studies and before and after photographs. Most major centres of medical education had adopted photography as a method of documentation and study by the 1900s. Many photographers were working in multi-faceted disciplines from radiology, pathology and ophthalmology. Medical photography became a special field of photography and in 1931 a group of photographers working in medicine came together at Yale University in the United States of America to form the Biological Photographic Association, which later became the Bio Communications Association Inc. The group published a journal; the Journal of Biological Photography which was later incorporated into the Journal of BioCommunication. Other organizations formed in England, Scandinavia and Australia. Photography continues today to play a role in medicine through documentation, research and education.

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Long Exposure Photography

All About Long Exposure Photography

Long-exposure photography or time-exposure photography or slow shutter photography involves using a long-duration shutter speed to sharply capture the stationary elements of images while blurring, smearing, or obscuring the moving elements. Long-exposure photography captures one element that conventional photography does not: time. The paths of bright moving objects become clearly visible. Clouds form broad bands, head and tail lights of cars become bright streaks, stars form trails in the sky and water smooths over. Only bright objects will form visible trails, however, dark objects usually disappear. Boats during daytime long exposures will disappear, but will form bright trails from their lights at night.

Whereas there is no fixed definition of what constitutes "long", the intent is to create a photo that somehow shows the effect of passing time, be it smoother waters or light trails. A 30-minute photo of a static object and surrounding cannot be distinguished from a short exposure, hence, the inclusion of motion is the main factor to add intrigue to long exposure photos. Images with exposure times of several minutes also tend to make moving people or dark objects disappear (because they are in any one spot for only a fraction of the exposure time), often adding a serene and otherworldly appearance to long exposure photos.

A long exposure photo of a watch in the dark. Note the appearance of the second hand as it rotates, showing that this was a 30-second exposure. The hour hand (which has only moved barely) is clear, while the minute hand is slightly blurry from a half a minute of movement.

When a scene includes both stationary and moving subjects (for example, a fixed street and moving cars or a camera within a car showing a fixed dashboard and moving scenery), a slow shutter speed can cause interesting effects, such as light trails.

Long exposures are easiest to accomplish in low-light conditions, but can be done in brighter light using neutral density filters or specially designed cameras. When using a dense neutral density filter your camera's auto focus will not be able to be able to function. It is best to compose and focus without the filter. Then once you are happy with the composition, switch to manual focus and put the neutral density filter back on.

Long-exposure photography is often used in a night-time setting, where the lack of light forces longer exposures, if maximum quality is to be retained. Increasing ISO sensitivity allows for shorter exposures, but substantially decreases image quality through reduced dynamic range and higher noise. By leaving the camera's shutter open for an extended period of time, more light is absorbed, creating an exposure that captures the entire dynamic range of the digital camera sensor or film. If the camera is stationary for the entire period of time that the shutter is open, a very vibrant and clear photograph can be produced.

A 30-second-long exposure sharply captured the still elements of this image while blurring the waterfall into a mist-like appearance. Debris in the swirling water in the pool forms complete circles.

Long exposures can blur moving water so it has mist-like qualities while keeping stationary objects like land and structures sharp.

A Solargraph taken from ESO's APEX at Chajnantor.

Solargraphy is a technique in which a fixed pinhole camera is used to expose photographic paper for an extremely long amount of time (sometimes half a year). It is most often used to show the path taken by the sun across the sky. One example of this is a single six-month exposure taken by photographer Justin Quinnell, showing sun-trails over Clifton Suspension Bridge between 19 December 2007 and 21 June 2008. Part of the Slow light: 6 months over Bristol exhibition, Quinnell describes the piece as capturing "a period of time beyond what we can perceive with our own vision." This method of solargraphy uses a simple pinhole camera securely fixed in a position which won't be disturbed. Quinnel constructed his camera from an empty drink can with a 0.25mm aperture and a single sheet of photographic paper.

On February 3, 2015 a pinhole camera used in a Georgia State University solargraphy art project was blown up by the Atlanta bomb squad. The device, one of nineteen placed throughout the city, had been duct-taped to the 14th Ave. bridge above I-75/85; traffic was shut down for two hours, and the remaining cameras were later removed by authorities.

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All About High Speed Photography

High Speed Photography

High-speed photography is the science of taking pictures of very fast phenomena. In 1948, defined high-speed photography as any set of photographs captured by a camera capable of 69 frames per second or greater, and of at least three consecutive frames. High-speed photography can be considered to be the opposite of time-lapse photography.

In common usage, high-speed photography may refer to either or both of the following meanings. The first is that the photograph itself may be taken in a way as to appear to freeze the motion, especially to reduce motion blur. The second is that a series of photographs may be taken at a high sampling frequency or frame rate. The first requires a sensor with good sensitivity and either a very good shuttering system or a very fast strobe light. The second requires some means of capturing successive frames, either with a mechanical device or by moving data off electronic sensors very quickly.

Other considerations for high-speed photographers are record length, reciprocity breakdown, and spatial resolution.

The first practical application of high-speed photography was Eadweard Muybridge's 1878 investigation into whether horses' feet were actually all off the ground at once during a gallop. The first photograph of a supersonic flying bullet was taken by the Austrian physicist Peter Salcher in Rijeka in 1886, a technique that was later used by Ernst Machin his studies of supersonic motion. German weapons scientists applied the techniques in 1916.

Bell Telephone Laboratories was one of the first customers for a camera developed by Eastman Kodak in the early 1930s. Bell used the system, which ran 16 mm film at 1000 frame/s and had a 100-foot (30 m) load capacity, to study relay bounce. When Kodak declined to develop a higher-speed version, Bell Labs developed it themselves, calling it the Fastax. The Fastax was capable of 5,000 frame/s. Bell eventually sold the camera design to Western Electric, who in turn sold it to the Wollensak Optical Company. Wollensak further improved the design to achieve 10,000 frame/s. Redlake Laboratories introduced another 16 mm rotating prism camera, the Hycam, in the early 1960s. Photo-Sonics Developed several models of rotating prism camera capable of running 35 mm and 70 mm film in the 1960s. Visible Solutions Introduced the Photec IV 16 mm camera in the 1980s.

In 1940, a patent was filed by Cearcy D. Miller for the rotating mirror camera, theoretically capable of one million frames per second. The first practical application of this idea was during the Manhattan Project, when Berlin Brixner, the photographic technician on the project, built the first known fully functional rotating mirror camera. This camera was used to photograph early prototypes of the first nuclear bomb, and resolved a key technical issue about the shape and speed of the implosion, that had been the source of an active dispute between the explosives engineers and the physics theoreticians.

The D. B. Milliken company developed an intermittent, pin-registered, 16 mm camera for speeds of 400 frame/s in 1957. Mitchell,Redlake Laboratories, and Photo-Sonics eventually followed in the 1960s with a variety of 16, 35, and 70 mm intermittent cameras.

Harold Edgerton is generally credited with pioneering the use of the stroboscope to freeze fast motion. He eventually helped found EG&G, which used some of Edgerton's methods to capture the physics of explosions required to detonate nuclear weapons. One such device was the EG&G Microflash 549, which is an air-gap flash. Also see the photograph of an explosion using a Rapatronic camera.

Advancing the idea of the stroboscope, researchers began using lasers to stop high-speed motion. Recent advances include the use of High Harmonic Generation to capture images of molecular dynamics down to the scale of the attosecond (10⁻¹⁸ s).

Main high-speed camera is defined as having the capability of capturing video at a rate in excess of 250 frames per second. There are three types of high-speed film cameras;

Intermittent motion cameras, which are a speed-up version of the standard motion picture camera using a sewing machine type mechanism to advance the film intermittently to a fixed exposure point behind the objective lens,Rotating prism cameras, which pull a long reel of film continuously past an exposure point and use a rotating prism between the objective lens and the film to impart motion to the image which matches the film motion, thereby canceling it out, and Rotating mirror cameras, which relay the image through a rotating mirror to an arc of film, and can only work in a burst mode.

Intermittent motion cameras are capable of hundreds of frames per second. Rotating prism cameras are capable of thousands of frames per second. Rotating mirror cameras are capable of millions of frames per second.

As film and mechanical transports improved, the high-speed film camera became available for scientific research. Kodak eventually shifted its film from acetate base to Estar (Kodak's name for a Mylar-equivalent plastic), which enhanced the strength and allowed it to be pulled faster. The Estar was also more stable than acetate allowing more accurate measurement, and it was not as prone to fire.

Each film type is available in many load sizes. These may be cut down and placed in magazines for easier loading. A 1,200-foot (370 m) magazine is typically the longest available for the 35 mm and 70 mm cameras. A 400-foot (120 m) magazine is typical for 16 mm cameras, though 1,000-foot (300 m) magazines are available. Typically rotary prism cameras use 100 ft (30m) film loads. The images on 35 mm high-speed film are typically more rectangular with the long side between the sprocket holes instead of parallel to the edges as in standard photography. 16 mm and 70 mm images are typically more square rather than rectangular. A list of ANSI formats and sizes is available.

Most cameras use pulsed timing marks along the edge of the film (either inside or outside of the film perforations) produced by sparks or later by LEDs. These allow accurate measurement of the film speed and in the case of streak or smear images, velocity measurement of the subject. These pulses are usually cycled at 10, 100, 1000 Hz depending on the speed setting of the camera.

Just as with a standard motion picture camera, the intermittent register pin camera actually stops the film in the film gate while the photograph is being taken. In high-speed photography, this requires some modifications to the mechanism for achieving this intermittent motion at such high speeds. In all cases, a loop is formed before and after the gate to create and then take up the slack.Pulldown claws, which enter the film through perforations, pulling it into place and then retracting out of the perforations and out of the film gate, are multiplied to grab the film through multiple perforations in the film, thereby reducing the stress that any individual perforation is subjected to. Register pins,which secure the film through perforations in final position while it is being exposed, after the pulldown claws are retracted are also multiplied, and often made from exotic materials. In some cases, vacuum suction is used to keep the film, especially 35 mm and 70 mm film, flat so that the images are in focus across the entire frame.

16 mm pin register: D. B. Milliken Locam, capable of 500 frame/s; the design was eventually sold to Redlake. Photo-Sonics built a 16 mm pin-registered camera that was capable of 1000 frame/s, but they eventually removed it from the market.35 mm pin register: Early cameras included the Mitchell 35 mm. Photo-Sonics won an Academy Award for Technical Achievement for the 4ER in 1988.^[14] The 4E is capable of 360 frame/s.70 mm pin register: Cameras include a model made by Hulcher, and Photo-Sonics 10A and 10R cameras, capable of 125 frame/s.

The rotary prism camera allowed higher frame rates without placing as much stress on the film or transport mechanism. The film moves continuously past a rotating prism which is synchronized to the main film sprocket such that the speed of the film and the speed of the prism are always running at the same proportional speed. The prism is located between the objective lens and the film, such that the revolution of the prism "paints" a frame onto the film for each face of the prism. Prisms are typically cubic, or four sided, for full frame exposure. Since exposure occurs as the prism rotates, images near the top or bottom of the frame, where the prism is substantially off axis, suffer from significant aberration. A shutter can improve the results by gating the exposure more tightly around the point where the prism faces are nearly parallel.

16 mm rotary prism - Redlake Hycam and Fastax cameras are capable of 10,000 frame/s with a full frame prism (4 facets), 20,000 frame/s with a half-frame kit, and 40,000 frame/s with a quarter-frame kit. Visible Solutions also makes the Photec IV.35 mm rotary prism - Photo-Sonics 4C cameras are capable of 2,500 frame/s with a full frame prism (4 facets), 4,000 frame/s with a half-frame kit, and 8,000 frame/s with a quarter-frame kit.70 mm rotary prism - Photo-Sonics 10B cameras are capable of 360 frame/s with a full frame prism (4 facets), and 720 frame/s with a half-frame kit.

Rotating Mirror cameras can be divided into two sub-categories; pure rotating mirror cameras and rotating drum, or Dynafax cameras.

In pure rotating mirror cameras, film is held stationary in an arc centered about a rotating mirror. The image formed by the objective lens is relayed back to the rotating mirror from a primary lens or lens group, and then through a secondary relay lens (or more typically lens group) which relays the image from the mirror to the film. For each frame formed on the film, one secondary lens group is required. As such, these cameras typically do not record more than one hundred frames. This means they record for only a very short time - typically less than a millisecond. Therefore, they require specialized timing and illumination equipment. Rotating mirror cameras are capable of up to 25 million frames per second, with typical speed in the millions of fps.

The rotating drum, or Dynafax, camera works by holding a strip of film in a loop on the inside track of a rotating drum. This drum is then spun up to the speed corresponding to a desired framing rate. The image is still relayed to an internal rotating mirror centered at the arc of the drum. The mirror is multi-faceted, typically having six to eight faces. Only one secondary lens is required, as the exposure always occurs at the same point. The series of frames is formed as the film travels across this point. Discrete frames are formed as each successive face of the mirror passes through the optical axis. Rotating drum cameras are capable of speed from the tens of thousands to hundreds of thousands of frames per second.

In both types of rotating mirror cameras, double exposure can occur if the system is not controlled properly. In a pure rotating mirror camera, this happens if the mirror makes a second pass across the optics while light is still entering the camera. In a rotating drum camera, it happens if the drum makes more than one revolution while light is entering the camera. Typically this is controlled by using fast extinguishing xenon strobe light sources that are designed to produce a flash of only a specific duration.

Rotating mirror camera technology has more recently been applied to electronic imaging, where instead of film, an array of single shot CCD or CMOS cameras is arrayed around the rotating mirror. This adaptation enables all of the advantages of electronic imaging in combination with the speed and resolution of the rotating mirror approach. Speeds up to 25 million frames per second are achievable, with typical speeds in the millions of fps.

Commercial availability of both types of rotating mirror cameras began in the 1950s with Beckman & Whitley, and Cordin Company. Beckman & Whitley sold both rotating mirror and rotating drum cameras, and coined the "Dynafax" term. Cordin Company sold only rotating mirror cameras. In the mid-1960s, Cordin Company bought Beckman & Whitley and has been the sole source of rotating mirror cameras since. An offshoot of Cordin Company, Millisecond Cinematography, provided drum camera technology to the commercial cinematography market.

Streak photography (closely related to strip photography) uses a streak camera to combine a series of essentially one-dimensional images into a two-dimensional image. The terms "streak photography" and "strip photography" are often interchanged, though some authors draw a distinction. 

By removing the prism from a rotary prism camera and using a very narrow slit in place of the shutter, it is possible to take images whose exposure is essentially one dimension of spatial information recorded continuously over time. Streak records are therefore a space vs. time graphical record. The image that results allows for very precise measurement of velocities. It is also possible to capture streak records using rotating mirror technology at much faster speeds. Digital line sensors can be used for this effect as well, as can some two-dimensional sensors with a slit mask.

For the development of explosives the image of a line of sample was projected onto an arc of film via a rotating mirror. The advance of flame appeared as an oblique image on the film, from which the velocity of detonation was measured.

Motion compensation photography (also known as ballistic synchro photography or smear photography when used to image high-speed projectiles) is a form of streak photography. When the motion of the film is opposite to that of the subject with an inverting (positive) lens, and synchronized appropriately, the images show events as a function of time. Objects remaining motionless show up as streaks. This is the technique used for finish line photographs. At no time is it possible to take a still photograph that duplicates the results of a finish line photograph taken with this method. A still is a photograph in time, a streak/smear photograph is a photograph of time. When used to image high-speed projectiles the use of a slit (as in streak photography) produce very short exposure times ensuring higher image resolution. The use for high-speed projectiles means that one still image is normally produced on one roll of cine film. From this image information such as yaw or pitch can be determined. Because of its measurement of time variations in velocity will also be shown by lateral distortions of the image.

By combining this technique with a diffracted wavefront of light, as by a knife-edge, it is possible to take photographs of phase perturbations within a homogeneous medium. For example, it is possible to capture shock waves of bullets and other high-speed objects. See, for example, shadowgraph and schlieren photography.

In December 2011, a research group at MIT reported a combined implementation of the laser (stroboscopic) and streak camera applications to capture images of a repetitive event that can be reassembled to create a trillion-frame-per-second video. This rate of image acquisition, which enables the capture of images of moving photons, is possible by the use of the streak camera to collect each field of view rapidly in narrow single streak images. Illuminating a scene with a laser that emits pulses of light every 13 nanoseconds, synchronized to the streak camera with repeated sampling and positioning, researchers have demonstrated collection of one-dimensional data which can be computationally compiled into a two-dimensional video. Although this approach is limited by time resolution to repeatable events, stationary applications such as medical ultrasound or industrial material analysis are possibilities.

Source: Wikipedia

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All About Aerial Photography

Aerial Photography

Aerial photography is the taking of photographs of the ground from an elevated/direct-down position. Usually the camera is not supported by a ground-based structure. Platforms for aerial photography include fixed wing aircraft, helicopters,multi rotor Unmanned Aircraft Systems (UAS),balloons, blimps and dirigibles, rockets,pigeons, kites, parachutes, stand-alone telescoping and vehicle-mounted poles. Mounted cameras may be triggered remotely or automatically; hand-held photographs may be taken by a photographer.

Aerial photography should not be confused with air-to-air photography, where one or more aircraft are used as chase planes that "chase" and photograph other aircraft in flight.

Aerial photography was first practiced by the French photographer and balloonist Gaspard-Félix Tournachon, known as "Nadar", in 1858 over Paris, France. However, the photographs he produced no longer exist and therefore the earliest surviving aerial photograph is titled 'Boston, as the Eagle and the Wild Goose See It.' Taken by James Wallace Black and Samuel Archer King on October 13, 1860, it depicts Boston from a height of 630m.

Kite aerial photography was pioneered by British meteorologist E.D. Archibald in 1882. He used an explosive charge on a timer to take photographs from the air. Frenchman Arthur Batut began using kites for photography in 1888, and wrote a book on his methods in 1890. Samuel Franklin Cody Developed his advanced 'Man-lifter War Kite' and succeeded in interesting the British War Office with its capabilities.

The first use of a motion picture camera mounted to a heavier-than-air aircraft took place on April 24, 1909 over Rome in the 3:28 silent film short, Wilbur Wright und seine Flugmaschine.

The use of aerial photography rapidly matured during the war, as reconnaissance aircraft were equipped with cameras to record enemy movements and defences. At the start of the conflict, the usefulness of aerial photography was not fully appreciated, with reconnaissance being accomplished with map sketching from the air.

Germany adopted the first aerial camera, aGörz, in 1913. The French began the war with several squadrons of Blériot observation aircraft equipped with cameras for reconnaissance. The French Army developed procedures for getting prints into the hands of field commanders in record time.

Frederick Charles Victor Laws started aerial photography experiments in 1912 with No.1 Squadron of the Royal Flying Corps (later No. 1 Squadron RAF), taking photographs from the British dirigible Beta. He discovered that vertical photos taken with 60% overlap could be used to create a stereoscopic effect when viewed in a stereoscope, thus creating a perception of depth that could aid in cartography and in intelligence derived from aerial images. The Royal Flying Corps recon pilots began to use cameras for recording their observations in 1914 and by the Battle of Neuve Chapelle in 1915, the entire system of German trenches was being photographed. In 1916 the Austro-Hungarian Monarchy made vertical camera axis aerial photos above Italy for map-making.

The first purpose-built and practical aerial camera was invented by Captain John Moore-Brabazon in 1915 with the help of the Thornton-Pickard company, greatly enhancing the efficiency of aerial photography. The camera was inserted into the floor of the aircraft and could be triggered by the pilot at intervals. Moore-Brabazon also pioneered the incorporation of stereoscopic techniques into aerial photography, allowing the height of objects on the landscape to be discerned by comparing photographs taken at different angles.

By the end of the war aerial cameras had dramatically increased in size and focal power and were used increasingly frequently as they proved their pivotal military worth; by 1918 both sides were photographing the entire front twice a day, and had taken over half a million photos since the beginning of the conflict. In January 1918, General Allenby Used five Australian pilots from No. 1 Squadron AFC to photograph a 624 square miles (1,620 km²) area in Palestine as an aid to correcting and improving maps of the Turkish front. This was a pioneering use of aerial photography as an aid for cartography. Lieutenants Leonard Taplin, Allan Runciman Brown, H. L. Fraser, Edward Patrick Kenny, and L. W. Rogers photographed a block of land stretching from the Turkish front lines 32 miles (51 km) deep into their rear areas. Beginning 5 January, they flew with a fighter escort to ward off enemy fighters. Using Royal Aircraft Factory BE.12 and Martinsyde Airplanes, they not only overcame enemy air attacks, but also had to contend with 65 mph (105 km/h) winds, antiaircraft fire, and malfunctioning equipment to complete their task. 

The first commercial aerial photography company in the UK was Aerofilms Ltd, founded by World War I veterans Francis Wills and Claude Graham White in 1919. The company soon expanded into a business with major contracts in Africa and Asia as well as in the UK. Operations began from the Stag Lane Aerodrome at Edgware, using the aircraft of the London Flying School. Subsequently the Aircraft Manufacturing Company (later the De Havilland Aircraft Company), hired an Airco DH.9 along with pilot entrepreneur Alan Cobham.

From 1921, Aerofilms carried out vertical photography for survey and mapping purposes. During the 1930s, the company pioneered the science of photogrammetry(mapping from aerial photographs), with the Ordnance Survey amongst the company's clients.

Another successful pioneer of the commercial use of aerial photography was the American Sherman Fairchild who started his own aircraft firm Fairchild Aircraft to develop and build specialized aircraft for high altitude aerial survey missions. One Fairchild aerial survey aircraft in 1935 carried unit that combined two synchronized cameras, and each camera having five six inch lenses with a ten-inch lenses and took photos from 23,000 feet. Each photo covered two hundred and twenty five square miles. One of its first government contracts was an aerial survey of New Mexico to study soil erosion. A year later, Fairchild introduced a better high altitude camera with nine-lens in one unit that could take a photo of 600 square miles with each exposure from 30,000 feet.

In 1939 Sidney Cotton and Flying Officer Maurice Longbottom of the RAF were among the first to suggest that airborne reconnaissance may be a task better suited to fast, small aircraft which would use their speed and high service ceiling to avoid detection and interception. Although this seems obvious now, with modern reconnaissance tasks performed by fast, high flying aircraft, at the time it was radical thinking.

They proposed the use of Spitfires with their armament and radios removed and replaced with extra fuel and cameras. This led to the development of the Spitfire PR variants. Spitfires proved to be extremely successful in their reconnaissance role and there were many variants built specifically for that purpose. They served initially with what later became No. 1 Photographic Reconnaissance Unit (PRU). In 1928, the RAF developed an electric heating system for the aerial camera. This allowed reconnaissance aircraft to take pictures from very high altitudes without the camera parts freezing. Based at RAF Medmenham, the collection and interpretation of such photographs became a considerable enterprise.

Cotton's aerial photographs were far ahead of their time. Together with other members of the 1 PRU, he pioneered the techniques of high-altitude, high-speed stereoscopic photographs that were instrumental in revealing the locations of many crucial military and intelligence targets. According to R.V. Jones, photographs were used to establish the size and the characteristic launching mechanisms for both the V-1 flying bomb and the V-2 rocket. Cotton also worked on ideas such as a prototype specialist reconnaissance aircraft and further refinements of photographic equipment. At the peak, the British flew over 100 reconnaissance flights a day, yielding 50,000 images per day to interpret. Similar efforts were taken by other countries. 

Aerial photography is used in cartography (particularly in photogrammetric surveys, which are often the basis for topographic maps) , land-use planning, archaeology, movie production,environmental studies, power line inspection,  surveillance, commercial advertising, conveyancing, and artistic projects. An example of how aerial photography is used in the field of archaeology is the mapping project done at the site Angkor Borei in Cambodia from 1995-1996. Using aerial photography, archaeologists were able to identify archaeological features, including 112 water features (reservoirs, artificially constructed pools and natural ponds) within the walled site of Angkor Borei. In the United States, aerial photographs are used in many Phase I Environmental Site Assessments for property analysis. 

Advances in radio controlled models have made it possible for model aircraft to conduct low-altitude aerial photography. This had benefited real-estate advertising, where commercial and residential properties are the photographic subject when in 2014 the US Federal Communications Commission, issued an order banning the use of "Drones" in any commercial application related to photographs for use in real estate advertisement's. Small scale model aircraft offer increased photographic access to these previously restricted areas. Miniature vehicles do not replace full size aircraft, as full size aircraft are capable of longer flight times, higher altitudes, and greater equipment payloads. They are, however, useful in any situation in which a full-scale aircraft would be dangerous to operate. Examples would include the inspection of transformers atop power transmission lines and slow, low-level flight over agricultural fields, both of which can be accomplished by a large-scale radio controlled helicopter. Professional-grade, gyroscopically stabilized camera platforms are available for use under such a model; a large model helicopter with a 26cc gasoline engine can hoist a payload of approximately seven kilograms (15 lbs). In addition to gyroscopically stabilized footage, the use of RC copters as reliable aerial photography tools increased with the integration of FPV (first-person-view) technology. Many radio-controlled aircraft are now capable of utilizing Wi-Fi to stream live video from the aircraft's camera back to the pilot's ground station.

In Australia Civil Aviation Safety Regulation 101 (CASR 101) allows for commercial use of radio control aircraft. Under these regulations radio controlled unmanned aircraft for commercial are referred to as Unmanned Aircraft Systems (UAS), where as radio controlled aircraft for recreational purposes are referred to as model aircraft. Under CASR 101, businesses/persons operating radio controlled aircraft commercially are required to hold an operator certificate, just like manned aircraft operators. Pilots of radio controlled aircraft operating commercially are also required to be licensed by the Civil Aviation Safety Authority (CASA). Whilst a small UAS and model aircraft may actually be identical, unlike model aircraft, a UAS may enter controlled airspace with approval, and operate within close proximity to an aerodrome.

Due to a number of illegal operators in Australia making false claims of being approved, CASA maintains and publishes a list of approved UAS operators.

Recent (2006) FAA regulations grounding all commercial RC model flights have been upgraded to require formal FAA certification before permission is granted to fly at any altitude in the US.

June 25, 2014, The FAA, in ruling 14 CFR Part 91 [Docket No. FAA–2014–0396] "Interpretation of the Special Rule for Model Aircraft", banned the commercial use of unmanned aircraft over U.S. airspace. On September 26, 2014, the FAA began granting the right to use drones in aerial filmmaking. Operators are required to be licensed pilots and must keep the drone in view at all times. Drones cannot be used to film in areas where people might be put at risk.

On February 14, 2012, the President signed into law the FAA Modernization and Reform Act of 2012 (Pub. L. 112–95) (the Act), which established, in Section 336, a special rule for model aircraft. In Section 336, Congress confirmed the FAA’s long-standing position that model aircraft are aircraft. Under the terms of the Act, a model aircraft is defined as "an unmanned aircraft" that is "(1) capable of sustained flight in the atmosphere; (2) flown within visual line of sight of the person operating the aircraft; and (3) flown for hobby or recreational purposes."

Because anything capable of being viewed from a public space is considered outside the realm of privacy in the United States, aerial photography may legally document features and occurrences on private property.

The FAA can pursue enforcement action against persons operating model aircraft who endanger the safety of the national airspace system. Public Law 112–95, section 336(b).

Vertical photographs are taken straight down. They are mainly used in photogrammetry and image interpretation. Pictures that will be used in photogrammetry are traditionally taken with special large format cameras with calibrated and documented geometric properties.

Aerial photographs are often combined. Depending on their purpose it can be done in several ways, of which a few are listed below.

Panoramas can be made by stitchingseveral photographs taken with one hand held camera.In pictometry five rigidly mounted cameras provide one vertical and four low oblique pictures that can be used together.In some digital cameras for aerial photogrammetry images from several imaging elements, sometimes with separate lenses, are geometrically corrected and combined to one image in the camera.

Vertical photographs are often used to create orthophotos, alternatively known as orthophoto maps, photographs which have been geometrically "corrected" so as to be usable as a map. In other words, an orthophoto is a simulation of a photograph taken from an infinite distance, looking straight down to nadir. Perspective must obviously be removed, but variations in terrain should also be corrected for. Multiple geometric transformations are applied to the image, depending on the perspective and terrain corrections required on a particular part of the image.

Orthophotos are commonly used in geographic information systems, such as are used by mapping agencies (e.g. Ordnance Survey) to create maps. Once the images have been aligned, or "registered", with known real-world coordinates, they can be widely deployed.

Large sets of orthophotos, typically derived from multiple sources and divided into "tiles" (each typically 256 x 256 pixels in size), are widely used in online map systems such as Google Maps. OpenStreetMap offers the use of similar orthophotos for deriving new map data. Google Earth overlays orthophotos or satellite imagery onto a digital elevation model to simulate 3D landscapes.

Source: Wikipedia

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