An image of Orion's Belt
composited from digitized black-and-white photographic plates recorded
through red and blue astronomical filters, with a computer synthesized
green channel. The plates were taken using the Samuel Oschin Telescope between 1987 and 1991.
Astrophotography is a specialized type of photography for recording photos of astronomical objects, celestial events, and areas of the night sky. The first photograph of an astronomical object (the Moon)
was taken in 1840, but it was not until the late 19th century that
advances in technology allowed for detailed stellar photography. Besides
being able to record the details of extended objects such as the Moon, Sun, and planets, astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time.
Photography revolutionized the field of professional astronomical
research, with longtime exposures recording hundreds of thousands of
new stars and nebulae that were invisible to the human eye, leading to
specialized and ever larger optical telescopes that were essentially big cameras designed to record light using photographic plates.
Astrophotography had an early role in sky surveys and star
classification but over time it has given way to more sophisticated
equipment and techniques designed for specific fields of scientific
research, with image sensors becoming just one of many forms of sensor.
Today, astrophotography is mostly a subdiscipline in amateur astronomy, usually seeking aesthetically pleasing images rather than scientific data. Amateurs use a wide range of special equipment and techniques.
With a few exceptions, astronomical photography employs long exposures since both film and digital imaging devices can accumulate and light photons
over long periods of time. The amount of light hitting the film or
detector is also increased by increasing the diameter of the primary
optics (the objective) being used. Urban areas produce light pollution
so equipment and observatories doing astronomical imaging are often
located in remote locations to allow long exposures without the film or
detectors being swamped with stray light.
Since the Earth is constantly rotating, telescopes and equipment
are rotated in the opposite direction to follow the apparent motion of
the stars overhead (called diurnal motion). This is accomplished by using either equatorial or computer-controlled altazimuth telescope mounts to keep celestial objects centered while the earth rotates. All telescope mount
systems suffer from induced tracking errors due to imperfect motor
drives, mechanical sag of the telescope and atmospheric refraction.
Tracking errors are corrected by keeping a selected aiming point,
usually a guide star, centered during the entire exposure. Sometimes (as in the case of comets)
the object to be imaged is moving, so the telescope has to be kept
constantly centered on that object. This guiding is done through a
second co-mounted telescope called a "guide scope" or via some type of "off-axis guider", a device with a prism or optical beam splitter
that allows the observer to view the same image in the telescope that
is taking the picture. Guiding was formerly done manually throughout the
exposure with an observer standing at (or riding inside) the telescope
making corrections to keep a cross hair
on the guide star. Since the advent of computer-controlled systems this
is accomplished by an automated systems in professional and even
amateur equipment.
Astronomical photography was one of the earliest types of scientific photography and almost from its inception it diversified into subdisciplines that each have a specific goal including star cartography, astrometry, stellar classification, photometry, spectroscopy, polarimetry, and the discovery of astronomical objects such as asteroids, meteors, comets, variable stars, novae, and even unknown planets. These often require specialized equipment such as telescopes designed for precise imaging, for wide field of view (such as Schmidt cameras), or for work at specific wavelengths of light. Astronomical CCD cameras may cool the sensor to reduce thermal noise and to allow the detector to record images in other spectra such as in infrared astronomy. Specialized filters are also used to record images in specific wavelengths.
History
Henry Draper with a refractor telescope set up for photography (photo probably taken in the 1860s or early 1870).[3]
The development of astrophotography as a scientific tool was
pioneered in the mid-19th century for the most part by experimenters and
amateur astronomers, or so-called "gentleman scientists" (although, as in other scientific fields, these were not always men).
Because of the very long exposures needed to capture relatively faint
astronomical objects, many technological problems had to be overcome.
These included making telescopes rigid enough so they wouldn’t sag out
of focus during the exposure, building clock drives that could rotate
the telescope mount at a constant rate, and developing ways to
accurately keep a telescope aimed at a fixed point over a long period of
time. Early photographic processes also had limitations. The daguerreotype process was far too slow to record anything but the brightest objects, and the wet plate collodion process limited exposures to the time the plate could stay wet.
The first-known attempt at astronomical photography was by Louis Jacques Mandé Daguerre, inventor of the daguerreotype process which bears his name, who attempted in 1839 to photograph the Moon. Tracking errors in guiding the telescope during the long exposure meant the photograph came out as an indistinct fuzzy spot. John William Draper,
New York University Professor of Chemistry, physician and scientific
experimenter managed to make the first successful photograph of the moon
a year later on March 23, 1840, taking a 20-minute-long daguerreotype image using a 5-inch (13 cm) reflecting telescope.
The Sun may have been first photographed in an 1845 daguerreotype by the French physicists Léon Foucault and Hippolyte Fizeau.
A failed attempt to obtain a photograph of a Total Eclipse of the Sun
was made by the Italian physicist, Gian Alessandro Majocchi during an
eclipse of the Sun that took place in his home city of Milan, on July 8,
1842. He later gave an account of his attempt and the Daguerreotype
photographs he obtained, in which he wrote
"...a few minutes before and after totality an iodized plate
was exposed in a camera to the light of the thin crescent, and a
distinct image was obtained; but another plate exposed to the light of
the corona for two minutes during totality did not show the slightest
trace of photographic action. No photographic alteration was caused by
the light of the corona condensed by a lens for two minutes, during
totality, on a sheet of paper prepared with bromide of silver."
The first solar eclipse photograph taken on July 28, 1851 by a daguerrotypist named Berkowski.
The Sun's solar corona was first successfully imaged during the Solar eclipse of July 28, 1851.
Dr. August Ludwig Busch, the Director of the Königsberg Observatory
gave instructions for a local daguerreotypist named Johann Julius
Friedrich Berkowski to image the eclipse. Busch himself was not present
at Königsberg (now Kaliningrad, Russia), but preferred to observe the eclipse from nearby Rixhoft. The telescope used by Berkowski was attached to 61⁄2-inch (17 cm) Königsberg heliometer
and had an aperture of only 2.4 in (6.1 cm), and a focal length of
32 in (81 cm). Commencing immediately after the beginning of totality,
Berkowski exposed a daguerreotype plate for 84 seconds in the focus of
the telescope, and on development an image of the corona was obtained.
He also exposed a second plate for about 40 to 45 seconds but was
spoiled when the sun broke out from behind the moon. More detailed photographic studies of the Sun were made by the British astronomer Warren De la Rue starting in 1861.
Henry Draper's 1880 photograph of the Orion Nebula, the first ever taken.
One
of Andrew Ainslie Common's 1883 photographs of the same nebula, the
first to show that a long exposure could record stars and nebulae
invisible to the human eye.
Astronomical photography did not become a serious research tool until the late 19th century, with the introduction of dry plate photography. It was first used by Sir William Huggins and his wife Margaret Lindsay Huggins,
in 1876, in their work to record the spectra of astronomical objects.
In 1880 Henry Draper used the new dry plate process with
photographically corrected 11 in (28 cm) refracting telescope made by Alvan Clark to make a 51-minute exposure of the Orion Nebula, the first photograph of a nebula ever made. A breakthrough in astronomical photography came in 1883, when amateur astronomer Andrew Ainslie Common
used the dry plate process to record several images of the same nebula
in exposures up to 60 minutes with a 36 in (91 cm) reflecting telescope
that he constructed in the backyard of his home in Ealing, outside
London. These images for the first time showed stars too faint to be
seen by the human eye.
The first all-sky photographic astrometry project, Astrographic Catalogue and Carte du Ciel,
was started in 1887. It was conducted by 20 observatories all using
special photographic telescopes with a uniform design called normal astrographs,
all with an aperture of around 13 in (330 mm) and a focal length of
11 ft (3.4 m), designed to create images with a uniform scale on the
photographic plate of approximately 60 arcsecs/mm while covering a 2° × 2° field of view. The attempt was to accurately map the sky down to the 14th magnitude but it was never completed.
The beginning of the 20th century saw the worldwide construction
of refracting telescopes and sophisticated large reflecting telescopes
specifically designed for photographic imaging. Towards the middle of
the century, giant telescopes such as the 200 in (5.1 m) Hale Telescope and the 48 in (120 cm) Samuel Oschin telescope at Palomar Observatory were pushing the limits of film photography.
Some progress was made in the field of photographic emulsions and in the techniques of forming gas hypersensitization,
cryogenic cooling, and light amplification, but starting in the 1970s
after the invention of the CCD, photographic plates were gradually
replaced by electronic imaging in professional and amateur
observatories. CCD's are far more light sensitive, do not drop off in
sensitivity over long exposures the way film does ("reciprocity failure"),
have the ability to record in a much wider spectral range, and simplify
storage of information. Telescopes now use many configurations of CCD
sensors including linear arrays and large mosaics of CCD elements
equivalent to 100 million pixels, designed to cover the focal plane of
telescopes that formerly used 10–14-inch (25–36 cm) photographic plates.
The late 20th century saw advances in astronomical imaging take
place in the form of new hardware, with the construction of giant
multi-mirror and segmented mirror telescopes. It would also see the introduction of space based telescopes, such as the Hubble Space Telescope.
Operating outside the atmosphere’s turbulence, scattered ambient light
and the vagaries of weather allows the Hubble Space Telescope, with a
mirror diameter of 2.4 metres (94 in), to record stars down to the 30th
magnitude, some 100 times dimmer than what the 5-meter Mount Palomar
Hale telescope could record in 1949.
Amateur astrophotography
2
minute time exposure of the comet Hale-Bopp imaged using a camera on a
fixed tripod. The tree in the foreground was illuminated using a small
flashlight.
Astrophotography is a popular hobby among photographers and amateur
astronomers. Images of the night sky can be obtained with the most basic
film and digital cameras. For simple star trails,
no additional equipment may be necessary other than common tripods.
There is a wide range of commercial equipment geared toward basic and
advanced astrophotography. Amateur astronomers and amateur telescope makers also use homemade equipment and modified devices.
Conventional over-the-counter film has long been used for
astrophotography. Film exposures range from seconds to over an hour.
Commercially available color film stock is subject to reciprocal failure
over long exposures, in which sensitivity to light of different
wavelengths appears to drop off at different rates as the exposure time
increases, leading to a color shift in the image. This is compensated
for by using the same technique used in professional astronomy of taking
photographs at different wavelengths that are then combined to create a
correct color image. Since film is much slower than digital sensors,
tiny errors in tracking can be corrected without much noticeable effect
on the final image. Film astrophotography is becoming less popular due
to the lower ongoing costs, greater sensitivity and the convenience of digital photography.
Video of night sky made with DSLR camera'stime-lapse feature. Photographer added camera movement (motion control) making the camera track in a random direction off the normal equatorial axis.
Since the late 1990s amateurs have been following the professional
observatories in the switch from film to digital CCDs for astronomical
imaging. CCDs are more sensitive than film, allowing much shorter
exposure times, and have a linear response to light. Images can be
captured in many short exposures to create a synthetic long exposure.
Digital cameras also have minimal or no moving parts and the ability to
be operated remotely via an infrared remote or computer tethering,
limiting vibration. Simple digital devices such as webcams can be modified to allow access to the focal plane and even (after the cutting of a few wires), for long exposure
photography. Digital video cameras are also used. There are many
techniques and pieces of commercially manufactured equipment for
attaching digital single lens reflex(DSLR) cameras and even basic point and shoot cameras to telescopes. Consumer level digital cameras suffer from image noise over long exposures, so there are many techniques for cooling the camera, including cryogenic
cooling. Astronomical equipment companies also now offer a wide range
of purpose-built astronomical CCD cameras complete with hardware and
processing software. Many commercially available DSLR cameras have the
ability to take long time exposures combined with sequential (time-lapse) images allowing the photographer to create a motion picture of the night sky.
Post-processing
The
Pleiades Star Cluster photographed with a 6 megapixel digital SLR
camera connected to a 80mm refracting telescope piggybacked on a larger
telescope. Image is made from seven 180 second images combined and
processed in Photoshop with a noise reduction plugin.
Both digital camera images and scanned film images are usually adjusted in image processing
software to improve the image in some way. Images can be brightened and
manipulated in a computer to adjust color and increase the contrast.
More sophisticated techniques involve capturing multiple images
(sometimes thousands) to composite together in an additive process to
sharpen images to overcome atmospheric seeing, negating tracking issues, bringing out faint objects with a poor signal-to-noise ratio, and filtering out light pollution. Digital camera images may also need further processing to reduce the image noise from long exposures, including subtracting a “dark frame” and a processing called image stacking or "Shift-and-add". There are several commercial, freeware and free software packages available specifically for astronomical photographic image manipulation.
Hardware
Astrophotographic
hardware among non-professional astronomers varies widely, since the
photographers themselves range from general photographers shooting some
form of aesthetically pleasing images to very serious amateur
astronomers collecting data for scientific research. As a hobby,
astrophotography has many challenges that have to be overcome that
differ from conventional photography and from what is normally
encountered in professional astronomy.
NGC281, popularly the 'Pacman Nebula', imaged from a suburban location using a 130mm amateur telescope and a DSLR camera.
Since most people live in urban areas, equipment often needs to be portable so that it can be taken far away from the lights of major cities or towns to avoid urban light pollution.
Urban astrophotographers may use special light-pollution or narrow-band
filters and advanced computer processing techniques to remove ambient
urban light from the background of their images. They may also stick to
imaging bright targets like the moon and planets. Another method used by
amateurs to avoid light pollution is to set up, or rent time, on a
remotely operated telescope at a dark sky location. Other challenges
include setup and alignment of portable telescopes for accurate
tracking, working within the limitations of “off the shelf” equipment,
the endurance of monitoring equipment, and sometimes manually tracking
astronomical objects over long exposures in a wide range of weather
conditions.
Some camera manufacturers modify their products to be used as astrophotography cameras, such as Canon's EOS 60Da, based on the EOS 60D but with a modified infrared filter and a low-noise sensor with heightened hydrogen-alpha sensitivity for improved capture of red hydrogen emission nebulae.
There are also cameras specifically designed for amateur
astrophotography based on commercially available imaging sensors. They
may also allow the sensor to be cooled to reduce image noise in long
exposures, provide raw image readout and to be controlled from a
computer for automated imaging. Raw image readout allows later better
image processing by retaining all the original image data which along
with stacking can assist in imaging faint deep sky objects.
With very low light capability, a few specific models of webcams
are popular for Solar, Lunar and Planetary imaging. Mostly, these are
manually focused cameras containing a CCD sensor instead of the more
common CMOS. The lenses of these cameras are removed and then these are
attached to telescopes to record images, video or both. In newer
techniques, videos of very faint objects are taken and the sharpest
frames of the video are 'stacked' together to obtain a still image of
respectable contrast. The Philips PCVC 740K and SPC 900 are among the
few webcams liked by astrophotographers.
Equipment setups
An amateur astrophotography setup with an automated guide system connected to a laptop.
Fixed or tripod
The most basic types of astronomical photographs are made with
standard cameras and photographic lenses mounted in a fixed position or
on a tripod. Foreground objects or landscapes are sometimes composed in
the shot. Objects imaged are constellations,
interesting planetary configurations, meteors, and bright comets.
Exposure times must be short (under a minute) to avoid having the stars
point image become an elongated line due to the Earth's rotation. Camera
lens focal lengths are usually short, as longer lenses will show image
trailing in a matter of seconds. Allowing the stars to intentionally
become elongated lines in exposures lasting several minutes or even
hours, called “Star trails”, is an artistic technique sometimes used.
Tracking mounts
To achieve longer exposures without objects being blurred, some form
of tracking mount is usually employed to compensate for the Earth's
rotation, including commercial equatorial mounts and homemade equatorial
devices such as barn door trackers and equatorial platforms.
"Piggyback" photography
Piggyback astronomical photography is a method where a camera/lens is
mounted on an equatorially mounted astronomical telescope. The
telescope is used as a guide scope to keep the field of view centered
during the exposure. This allows the camera to use a longer exposure
and/or a longer focal length lens or even be attached to some form of
photographic telescope co-axial with the main telescope.
Telescope focal plane photography
In this type of photography the telescope itself is used as the
"lens" collecting light for the film or CCD of the camera. Although this
allows for the magnification and light gathering power of the telescope
to be used, it is one of the most difficult astrophotography methods.
This is because of the difficulties in centering and focusing sometimes
very dim objects in the narrow field of view, contending with magnified
vibration and tracking errors, and the added expense of equipment (such
as sufficiently sturdy telescope mounts, camera mounts, camera
couplers, off axis guiders, guide scopes, illuminated cross-hairs, or
auto-guiders mounted on primary telescope or the guide-scope.) There are
several different ways cameras (with removable lenses) are attached to
amateur astronomical telescopes including:
Prime focus – In this method the image produced by the
telescope falls directly on the film or CCD with no intervening optics
or telescope eyepiece.
Positive projection – A method in which the telescope eyepiece (eyepiece projection) or a positive lens (placed after the focal plane
of the telescope objective) is used to project a much more magnified
image directly onto the film or CCD. Since the image is magnified with a
narrow field of view this method is generally used for lunar and
planetary photography.
Negative projection – This method, like positive projection, produces a magnified image. A negative lens, usually a Barlow or a photographic teleconverter, is placed in the light cone before the focal plane of the telescope objective.
Compression – Compression uses a positive lens (also called a focal reducer),
placed in the converging cone of light before the focal plane of the
telescope objective, to reduce overall image magnification. It is used
on very long focal length telescopes, such as Maksutovs and Schmidt–Cassegrains, to obtain a wider field of view.
When the camera lens is not removed (or cannot be removed) a common method used is afocal photography, also called afocal projection.
In this method both the camera lens and the telescope eyepiece are
attached. When both are focused at infinity the light path between them
is parallel (afocal),
allowing the camera to basically photograph anything the observer can
see. This method works well for capturing images of the moon and
brighter planets, as well as narrow field images of stars and nebulae.
Afocal photography was common with early 20th century consumer level
cameras, since many models had non-removable lenses. It has grown in
popularity with the introduction of point and shoot digital cameras since most models also have non-removable lenses.
Remote Telescope Astrophotography
With
the development of fast Internet in the last part of the 20th century
along with advances in computer-controlled telescope mounts and CCD
cameras 'Remote Telescope' astronomy is now a viable means for amateur
astronomers not aligned with major telescope facilities to partake in
research and deep sky imaging. This enables the imager to control a
telescope a large distance away in a dark location. The observers can
image through the telescopes using CCD cameras.
Imaging can be done regardless of the location of the user or the
telescopes they wish to use. The digital data collected by the telescope
is then transmitted and displayed to the user by means of the Internet.
An example of a digital remote telescope operation for public use via
the Internet is The Bareket Observatory.
Examples of amateur astrophotography techniques
20sec exposure photograph taken with a tripod mounted DSLR camera with 18-55mm lens
Fixed tripod mounted camera capturing "star trails"
Star trails photographed in earth orbit from the International Space Station
Fixed tripod image of a solar eclipse using a digital-SLR camera with a 500 mm lens
1 minute exposure using ISO 800 film, wide angle lens, piggybacked on an equatorial telescope
The Moon photographed using the Afocal technique, using 10 seconds of video stacked to create a final image.
A composite of several Digital-SLR photos compiled in Photoshop taken via eyepiece projection from an 8-inch Schmidt Cassegrain telescope.
Saturn image using negative projection (Barlow lens) with a webcam attached to a 250mm Newtonian telescope. It is a composite images made from 10% of the best exposures out of 1200 images using freeware image stacking and sharpening software (Giotto)
Jupiter photographed using the Afocal technique, using 10 seconds of video stacked to create a final image.
Photography is the art, application and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing (e.g., photolithography),
and business, as well as its more direct uses for art, film and video
production, recreational purposes, hobby, and mass communication.
Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a digital image file for subsequent display or processing. The result with photographic emulsion is an invisible latent image, which is later chemically "developed" into a visible image, either negative or positive depending on the purpose of the photographic material and the method of processing. A negative image on film is traditionally used to photographically create a positive image on a paper base, known as a print, either by using an enlarger or by contact printing.
Etymology
The word "photography" was created from the Greek roots φωτός (phōtos), genitive of φῶς (phōs), "light" and γραφή (graphé) "representation by means of lines" or "drawing", together meaning "drawing with light".
Several people may have coined the same new term from these roots independently. Hercules Florence, a French painter and inventor living in Campinas, Brazil, used the French form of the word, photographie, in private notes which a Brazilian historian believes were written in 1834. This claim is widely reported but apparently has never been independently confirmed as beyond reasonable doubt.
The German newspaper Vossische Zeitung of 25 February 1839 contained an article entitled Photographie, discussing several priority claims – especially Henry Fox Talbot's – regarding Daguerre's claim of invention.
The article is the earliest known occurrence of the word in public
print. It was signed "J.M.", believed to have been Berlin astronomer Johann von Maedler.
Credit has traditionally been given to Sir John Herschel
both for coining the word and for introducing it to the public. His
uses of it in private correspondence prior to 25 February 1839 and at
his Royal Society lecture on the subject in London on 14 March 1839 have long been amply documented and accepted as settled facts.
The inventors Nicéphore Niépce, Henry Fox Talbot and Louis Daguerre
seem not to have known or used the word "photography", but referred to
their processes as "Heliography" (Niépce), "Photogenic
Drawing"/"Talbotype"/"Calotype" (Talbot) and "Daguerreotype" (Daguerre).
The discovery of the camera obscura that provides an image of a scene dates back to ancient China. Leonardo da Vinci
mentions natural camera obscura that are formed by dark caves on the
edge of a sunlit valley. A hole in the cave wall will act as a pinhole
camera and project a laterally reversed, upside down image on a piece of
paper. So the birth of photography was primarily concerned with
inventing means to capture and keep the image produced by the camera
obscura.
Renaissance
painters used the camera obscura which, in fact, gives the optical
rendering in color that dominates Western Art. The camera obscura
literally means "dark chamber" in Latin. It is a box with a hole in it which allows light to go through and create an image onto the piece of paper.
Around the year 1800, British inventor Thomas Wedgwood
made the first known attempt to capture the image in a camera obscura
by means of a light-sensitive substance. He used paper or white leather
treated with silver nitrate.
Although he succeeded in capturing the shadows of objects placed on the
surface in direct sunlight, and even made shadow copies of paintings on
glass, it was reported in 1802 that "the images formed by means of a
camera obscura have been found too faint to produce, in any moderate
time, an effect upon the nitrate of silver." The shadow images
eventually darkened all over.
Invention
Earliest known surviving heliographic engraving, 1825, printed from a metal plate made by Nicéphore Niépce.
The plate was exposed under an ordinary engraving and copied it by
photographic means. This was a step towards the first permanent
photograph taken with a camera.
The first permanent photoetching was an image produced in 1822 by the French inventor Nicéphore Niépce, but it was destroyed in a later attempt to make prints from it. Niépce was successful again in 1825. In 1826 or 1827, he made the View from the Window at Le Gras, the earliest surviving photograph from nature (i.e., of the image of a real-world scene, as formed in a camera obscura by a lens).
Because Niépce's camera photographs required an extremely long exposure (at least eight hours and probably several days), he sought to greatly improve his bitumen process or replace it with one that was more practical. In partnership with Louis Daguerre,
he worked out post-exposure processing methods that produced visually
superior results and replaced the bitumen with a more light-sensitive
resin, but hours of exposure in the camera were still required. With an
eye to eventual commercial exploitation, the partners opted for total
secrecy.
Niépce died in 1833 and Daguerre then redirected the experiments toward the light-sensitive silver halides,
which Niépce had abandoned many years earlier because of his inability
to make the images he captured with them light-fast and permanent.
Daguerre's efforts culminated in what would later be named the daguerreotype process. The essential elements—a silver-plated surface sensitized by iodine vapor, developed by mercury vapor, and "fixed" with hot saturated salt
water—were in place in 1837. The required exposure time was measured in
minutes instead of hours. Daguerre took the earliest confirmed
photograph of a person in 1838 while capturing a view of a Paris street:
unlike the other pedestrian and horse-drawn traffic on the busy
boulevard, which appears deserted, one man having his boots polished
stood sufficiently still throughout the several-minutes-long exposure to
be visible. The existence of Daguerre's process was publicly announced,
without details, on 7 January 1839. The news created an international
sensation. France soon agreed to pay Daguerre a pension in exchange for
the right to present his invention to the world as the gift of France,
which occurred when complete working instructions were unveiled on 19
August 1839. In that same year, American photographer Robert Cornelius is credited with taking the earliest surviving photographic self-portrait.
A latticed window in Lacock Abbey, England, photographed by William Fox Talbot in 1835. Shown here in positive form, this may be the oldest extant photographic negative made in a camera.
In Brazil, Hercules Florence had apparently started working out a silver-salt-based paper process in 1832, later naming it Photographie.
Meanwhile, a British inventor, William Fox Talbot,
had succeeded in making crude but reasonably light-fast silver images
on paper as early as 1834 but had kept his work secret. After reading
about Daguerre's invention in January 1839, Talbot published his
hitherto secret method and set about improving on it. At first, like
other pre-daguerreotype processes, Talbot's paper-based photography
typically required hours-long exposures in the camera, but in 1840 he
created the calotype process, which used the chemical development of a latent image
to greatly reduce the exposure needed and compete with the
daguerreotype. In both its original and calotype forms, Talbot's
process, unlike Daguerre's, created a translucent negative
which could be used to print multiple positive copies; this is the
basis of most modern chemical photography up to the present day, as
Daguerreotypes could only be replicated by rephotographing them with a
camera. Talbot's famous tiny paper negative of the Oriel window in Lacock Abbey, one of a number of camera photographs he made in the summer of 1835, may be the oldest camera negative in existence.
British chemist John Herschel made many contributions to the new field. He invented the cyanotype
process, later familiar as the "blueprint". He was the first to use the
terms "photography", "negative" and "positive". He had discovered in
1819 that sodium thiosulphate
was a solvent of silver halides, and in 1839 he informed Talbot (and,
indirectly, Daguerre) that it could be used to "fix" silver-halide-based
photographs and make them completely light-fast. He made the first glass negative in late 1839.
In the March 1851 issue of The Chemist, Frederick Scott Archer published his wet plate collodion process.
It became the most widely used photographic medium until the gelatin
dry plate, introduced in the 1870s, eventually replaced it. There are
three subsets to the collodion process; the Ambrotype (a positive image on glass), the Ferrotype or Tintype (a positive image on metal) and the glass negative, which was used to make positive prints on albumen or salted paper.
Many advances in photographic glass plates and printing were made during the rest of the 19th century. In 1891, Gabriel Lippmann introduced a process for making natural-color photographs based on the optical phenomenon of the interference
of light waves. His scientifically elegant and important but ultimately
impractical invention earned him the Nobel Prize in Physics in 1908.
Glass plates were the medium for most original camera photography
from the late 1850s until the general introduction of flexible plastic
films during the 1890s. Although the convenience of the film greatly
popularized amateur photography, early films were somewhat more
expensive and of markedly lower optical quality than their glass plate
equivalents, and until the late 1910s they were not available in the
large formats preferred by most professional photographers, so the new
medium did not immediately or completely replace the old. Because of the
superior dimensional stability of glass, the use of plates for some
scientific applications, such as astrophotography, continued into the 1990s, and in the niche field of laser holography, it has persisted into the 2010s.
Film
Undeveloped Arista black-and-white film, ISO 125/22°
Hurter and Driffield began pioneering work on the light sensitivity of photographic emulsions in 1876. Their work enabled the first quantitative measure of film speed to be devised.
The first flexible photographic roll film was marketed by George Eastman
in 1885, but this original "film" was actually a coating on a paper
base. As part of the processing, the image-bearing layer was stripped
from the paper and transferred to a hardened gelatin support. The first
transparent plastic roll film followed in 1889. It was made from highly
flammable nitrocellulose ("celluloid"), now usually called "nitrate film".
Although cellulose acetate or "safety film" had been introduced by Kodak in 1908,
at first it found only a few special applications as an alternative to
the hazardous nitrate film, which had the advantages of being
considerably tougher, slightly more transparent, and cheaper. The
changeover was not completed for X-ray
films until 1933, and although safety film was always used for 16 mm
and 8 mm home movies, nitrate film remained standard for theatrical
35 mm motion pictures until it was finally discontinued in 1951.
Films remained the dominant form of photography until the early
21st century when advances in digital photography drew consumers to
digital formats.
Although modern photography is dominated by digital users, film
continues to be used by enthusiasts and professional photographers. The
distinctive "look" of film based photographs compared to digital images
is likely due to a combination of factors, including: (1) differences in
spectral and tonal sensitivity (S-shaped density-to-exposure (H&D
curve) with film vs. linear response curve for digital CCD sensors) (2) resolution and (3) continuity of tone.
Originally, all photography was monochrome, or black-and-white.
Even after color film was readily available, black-and-white
photography continued to dominate for decades, due to its lower cost and
its "classic" photographic look. The tones and contrast between light
and dark areas define black-and-white photography.
It is important to note that monochromatic pictures are not necessarily
composed of pure blacks, whites, and intermediate shades of gray but
can involve shades of one particular hue depending on the process. The cyanotype process, for example, produces an image composed of blue tones. The albumen print process first used more than 170 years ago, produces brownish tones.
Many photographers continue to produce some monochrome images,
sometimes because of the established archival permanence of
well-processed silver-halide-based materials. Some full-color digital
images are processed using a variety of techniques to create
black-and-white results, and some manufacturers produce digital cameras
that exclusively shoot monochrome. Monochrome printing or electronic
display can be used to salvage certain photographs taken in color which
are unsatisfactory in their original form; sometimes when presented as
black-and-white or single-color-toned images they are found to be more
effective. Although color photography has long predominated, monochrome
images are still produced, mostly for artistic reasons. Almost all
digital cameras have an option to shoot in monochrome, and almost all
image editing software can combine or selectively discard RGB color channels to produce a monochrome image from one shot in color.
Color photography
was explored beginning in the 1840s. Early experiments in color
required extremely long exposures (hours or days for camera images) and
could not "fix" the photograph to prevent the color from quickly fading
when exposed to white light.
The first permanent color photograph was taken in 1861 using the
three-color-separation principle first published by Scottish physicist James Clerk Maxwell in 1855.
The foundation of virtually all practical color processes, Maxwell's
idea was to take three separate black-and-white photographs through red,
green and blue filters.
This provides the photographer with the three basic channels required
to recreate a color image. Transparent prints of the images could be
projected through similar color filters and superimposed on the
projection screen, an additive method of color reproduction. A color print on paper could be produced by superimposing carbon prints of the three images made in their complementary colors, a subtractive method of color reproduction pioneered by Louis Ducos du Hauron in the late 1860s.
Color photography was possible long before Kodachrome, as this 1903 portrait by Sarah Angelina Acland
demonstrates, but in its earliest years, the need for special
equipment, long exposures, and complicated printing processes made it
extremely rare.
Russian photographer Sergei Mikhailovich Prokudin-Gorskii
made extensive use of this color separation technique, employing a
special camera which successively exposed the three color-filtered
images on different parts of an oblong plate.
Because his exposures were not simultaneous, unsteady subjects
exhibited color "fringes" or, if rapidly moving through the scene,
appeared as brightly colored ghosts in the resulting projected or
printed images.
Implementation of color photography was hindered by the limited
sensitivity of early photographic materials, which were mostly sensitive
to blue, only slightly sensitive to green, and virtually insensitive to
red. The discovery of dye sensitization by photochemist Hermann Vogel
in 1873 suddenly made it possible to add sensitivity to green, yellow
and even red. Improved color sensitizers and ongoing improvements in the
overall sensitivity of emulsions steadily reduced the once-prohibitive long exposure times required for color, bringing it ever closer to commercial viability.
Autochrome, the first commercially successful color process, was introduced by the Lumière brothers in 1907. Autochrome plates incorporated a mosaic color filter layer made of dyed grains of potato starch,
which allowed the three color components to be recorded as adjacent
microscopic image fragments. After an Autochrome plate was reversal processed to produce a positive transparency,
the starch grains served to illuminate each fragment with the correct
color and the tiny colored points blended together in the eye,
synthesizing the color of the subject by the additive method.
Autochrome plates were one of several varieties of additive color
screen plates and films marketed between the 1890s and the 1950s.
Kodachrome, the first modern "integral tripack" (or "monopack") color film, was introduced by Kodak in 1935. It captured the three color components in a multi-layer emulsion. One layer was sensitized to record the red-dominated part of the spectrum, another layer recorded only the green part and a third recorded only the blue. Without special film processing, the result would simply be three superimposed black-and-white images, but complementary cyan, magenta, and yellow dye images were created in those layers by adding color couplers during a complex processing procedure.
Agfa's similarly structured Agfacolor
Neu was introduced in 1936. Unlike Kodachrome, the color couplers in
Agfacolor Neu were incorporated into the emulsion layers during
manufacture, which greatly simplified the processing. Currently,
available color films still employ a multi-layer emulsion and the same
principles, most closely resembling Agfa's product.
Instant color film,
used in a special camera which yielded a unique finished color print
only a minute or two after the exposure, was introduced by Polaroid in 1963.
Color photography may form images as positive transparencies, which can be used in a slide projector,
or as color negatives intended for use in creating positive color
enlargements on specially coated paper. The latter is now the most
common form of film (non-digital) color photography owing to the
introduction of automated photo printing equipment. After a transition
period centered around 1995–2005, color film was relegated to a niche
market by inexpensive multi-megapixel digital cameras. Film continues to
be the preference of some photographers because of its distinctive
"look".
Digital
In 1981, Sony unveiled the first consumer camera to use a charge-coupled device for imaging, eliminating the need for film: the Sony Mavica.
While the Mavica saved images to disk, the images were displayed on
television, and the camera was not fully digital. In 1991, Kodak
unveiled the DCS 100, the first commercially available digital single lens reflex camera. Although its high cost precluded uses other than photojournalism and professional photography, commercial digital photography was born.
Digital imaging uses an electronic image sensor to record the image as a set of electronic data rather than as chemical changes on film. An important difference between digital and chemical photography is that chemical photography resists photo manipulation because it involves film and photographic paper,
while digital imaging is a highly manipulative medium. This difference
allows for a degree of image post-processing that is comparatively
difficult in film-based photography and permits different communicative
potentials and applications.
Digital photography dominates the 21st century. More than 99% of
photographs taken around the world are through digital cameras,
increasingly through smartphones.
Synthesis
Synthesis photography is part of computer-generated imagery
(CGI) where the shooting process is modeled on real photography. The
CGI, creating digital copies of real universe, requires a visual
representation process of these universes. Synthesis photography is the
application of analog and digital photography
in digital space. With the characteristics of the real photography but
not being constrained by the physical limits of real world, synthesis
photography allows artists to move into areas beyond the grasp of real
photography.
Techniques
Angles such as vertical, horizontal, or as pictured here diagonal are considered important photographic techniques
A large variety of photographic techniques and media are used in the
process of capturing images for photography. These include the camera;
stereoscopy; dualphotography; full-spectrum, ultraviolet and infrared
media; light field photography; and other imaging techniques.
Cameras
The camera is the image-forming device, and a photographic plate, photographic film or a silicon electronic image sensor
is the capture medium. The respective recording medium can be the plate
or film itself, or a digital magnetic or electronic memory.
Photographers control the camera and lens to "expose" the light recording material to the required amount of light to form a "latent image" (on plate or film) or RAW file (in digital cameras) which, after appropriate processing, is converted to a usable image. Digital cameras use an electronic image sensor based on light-sensitive electronics such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology. The resulting digital image is stored electronically, but can be reproduced on a paper.
The camera (or 'camera obscura')
is a dark room or chamber from which, as far as possible, all light is
excluded except the light that forms the image. It was discovered and
used in the 16th century by painters. The subject being photographed,
however, must be illuminated. Cameras can range from small to very
large, a whole room that is kept dark while the object to be
photographed is in another room where it is properly illuminated. This
was common for reproduction photography of flat copy when large film
negatives were used.
As soon as photographic materials became "fast" (sensitive) enough for taking candid
or surreptitious pictures, small "detective" cameras were made, some
actually disguised as a book or handbag or pocket watch (the Ticka camera) or even worn hidden behind an Ascot necktie with a tie pin that was really the lens.
The movie camera
is a type of photographic camera which takes a rapid sequence of
photographs on recording medium. In contrast to a still camera, which
captures a single snapshot at a time, the movie camera takes a series of
images, each called a "frame". This is accomplished through an
intermittent mechanism. The frames are later played back in a movie
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.
Stereoscopic
Photographs, both monochrome and color, can be captured and displayed
through two side-by-side images that emulate human stereoscopic vision.
Stereoscopic photography was the first that captured figures in motion.
While known colloquially as "3-D" photography, the more accurate term
is stereoscopy. Such cameras have long been realized by using film and
more recently in digital electronic methods (including cell phone
cameras).
Dualphotography
An example of a dualphoto using a smartphone based app
Dualphotography consists of photographing a scene from both sides of a
photographic device at once (e.g. camera for back-to-back
dualphotography, or two networked cameras for portal-plane
dualphotography). The dualphoto apparatus can be used to simultaneously
capture both the subject and the photographer, or both sides of a
geographical place at once, thus adding a supplementary narrative layer
to that of a single image.
Ultraviolet and infrared
films have been available for many decades and employed in a variety of
photographic avenues since the 1960s. New technological trends in
digital photography have opened a new direction in full spectrum photography, where careful filtering choices across the ultraviolet, visible and infrared lead to new artistic visions.
Modified digital cameras can detect some ultraviolet, all of the
visible and much of the near infrared spectrum, as most digital imaging
sensors are sensitive from about 350 nm to 1000 nm. An off-the-shelf
digital camera contains an infrared hot mirror
filter that blocks most of the infrared and a bit of the ultraviolet
that would otherwise be detected by the sensor, narrowing the accepted
range from about 400 nm to 700 nm.
Replacing a hot mirror or infrared blocking filter with an
infrared pass or a wide spectrally transmitting filter allows the camera
to detect the wider spectrum light at greater sensitivity. Without the
hot-mirror, the red, green and blue (or cyan, yellow and magenta)
colored micro-filters placed over the sensor elements pass varying
amounts of ultraviolet (blue window) and infrared (primarily red and
somewhat lesser the green and blue micro-filters).
Digital methods of image capture and display processing have enabled
the new technology of "light field photography" (also known as synthetic
aperture photography). This process allows focusing at various depths
of field to be selected after the photograph has been captured. As explained by Michael Faraday in 1846, the "light field"
is understood as 5-dimensional, with each point in 3-D space having
attributes of two more angles that define the direction of each ray
passing through that point.
These additional vector attributes can be captured optically
through the use of microlenses at each pixel point within the
2-dimensional image sensor. Every pixel of the final image is actually a
selection from each sub-array located under each microlens, as
identified by a post-image capture focus algorithm.
Besides the camera, other methods of forming images with light are available. For instance, a photocopy or xerography machine forms permanent images but uses the transfer of static electrical charges rather than photographic medium, hence the term electrophotography. Photograms
are images produced by the shadows of objects cast on the photographic
paper, without the use of a camera. Objects can also be placed directly
on the glass of an image scanner to produce digital pictures.
Modes of production
Amateur
An amateur photographer is one who practices photography as a hobby/passion
and not necessarily for profit. The quality of some amateur work is
comparable to that of many professionals and may be highly specialized
or eclectic
in choice of subjects. Amateur photography is often pre-eminent in
photographic subjects which have little prospect of commercial use or
reward. Amateur photography grew during the late 19th century due to the
popularization of the hand-held camera.
Nowadays it has spread widely through social media and is carried out
throughout different platforms and equipment, switching to the use of
cell phone as a key tool for making photography more accessible to
everyone.
A photograph taken by an amateur photographer in Lebanon.
Indianapolis as a panorama and a modified fisheye image by an amateur photographer with image editing software
The same image but modified with a fisheye lens-style technique into a circle
Commercial
Example of a studio-made food photograph.
Commercial photography is probably best defined as any photography for which the photographer is paid for images rather than works of art.
In this light, money could be paid for the subject of the photograph or
the photograph itself. Wholesale, retail, and professional uses of
photography would fall under this definition. The commercial
photographic world could include:
Advertising photography: photographs made to illustrate and usually sell a service or product. These images, such as packshots, are generally done with an advertising agency, design firm or with an in-house corporate design team.
Fashion and glamour photography usually incorporates models and is a form of advertising photography. Fashion photography, like the work featured in Harper's Bazaar,
emphasizes clothes and other products; glamour emphasizes the model and
body form. Glamour photography is popular in advertising and men's magazines. Models in glamour photography sometimes work nude.
Concert photography
focuses on capturing candid images of both the artist or band as well
as the atmosphere (including the crowd). Many of these photographers
work freelance and are contracted through an artist or their management
to cover a specific show. Concert photographs are often used to promote
the artist or band in addition to the venue.
Crime scene photography consists of photographing scenes of crime such as robberies and murders. A black and white camera or an infrared camera may be used to capture specific details.
Still life photography
usually depicts inanimate subject matter, typically commonplace objects
which may be either natural or man-made. Still life is a broader
category for food and some natural photography and can be used for
advertising purposes.
Food photography
can be used for editorial, packaging or advertising use. Food
photography is similar to still life photography but requires some
special skills.
Editorial photography illustrates a story or idea within the context
of a magazine. These are usually assigned by the magazine and encompass
fashion and glamour photography features.
Photojournalism
can be considered a subset of editorial photography. Photographs made
in this context are accepted as a documentation of a news story.
Paparazzi
is a form of photojournalism in which the photographer captures candid
images of athletes, celebrities, politicians, and other prominent
people.
Pet photography involves several aspects that are similar to
traditional studio portraits. It can also be done in natural lighting,
outside of a studio, such as in a client's home.
Landscape 360-degree panoramic picture of the Chajnantor
plateau in the Atacama Desert, Chile. In the center is Cerro
Chajnantor itself. To the right, on the plateau, is the
The market for photographic services demonstrates the aphorism "A picture is worth a thousand words", which has an interesting basis in the history of photography. Magazines and newspapers, companies putting up Web sites, advertising agencies and other groups pay for photography.
Many people take photographs for commercial purposes.
Organizations with a budget and a need for photography have several
options: they can employ a photographer directly, organize a public
competition, or obtain rights to stock photographs. Photo stock can be procured through traditional stock giants, such as Getty Images or Corbis; smaller microstock agencies, such as Fotolia; or web marketplaces, such as Cutcaster.
During the 20th century, both fine art photography and documentary photography became accepted by the English-speaking art world and the gallery system. In the United States, a handful of photographers, including Alfred Stieglitz, Edward Steichen, John Szarkowski, F. Holland Day, and Edward Weston, spent their lives advocating for photography as a fine art.
At first, fine art photographers tried to imitate painting styles. This movement is called Pictorialism, often using soft focus for a dreamy, 'romantic' look. In reaction to that, Weston, Ansel Adams, and others formed the Group f/64 to advocate 'straight photography', the photograph as a (sharply focused) thing in itself and not an imitation of something else.
The aesthetics
of photography is a matter that continues to be discussed regularly,
especially in artistic circles. Many artists argued that photography was
the mechanical reproduction of an image. If photography is
authentically art, then photography in the context of art would need
redefinition, such as determining what component of a photograph makes
it beautiful to the viewer. The controversy began with the earliest images "written with light"; Nicéphore Niépce, Louis Daguerre,
and others among the very earliest photographers were met with acclaim,
but some questioned if their work met the definitions and purposes of
art.
Clive Bell in his classic essay Art states that only "significant form" can distinguish art from what is not art.
There must be some one quality
without which a work of art cannot exist; possessing which, in the least
degree, no work is altogether worthless. What is this quality? What
quality is shared by all objects that provoke our aesthetic emotions?
What quality is common to Sta. Sophia and the windows at Chartres,
Mexican sculpture, a Persian bowl, Chinese carpets, Giotto's frescoes at
Padua, and the masterpieces of Poussin, Piero della Francesca, and
Cezanne? Only one answer seems possible – significant form. In each,
lines and colors combined in a particular way, certain forms and
relations of forms, stir our aesthetic emotions.
On 7 February 2007, Sotheby's London sold the 2001 photograph 99 Cent II Diptychon for an unprecedented $3,346,456 to an anonymous bidder, making it the most expensive at the time.
Conceptual photography
turns a concept or idea into a photograph. Even though what is depicted
in the photographs are real objects, the subject is strictly abstract.
Photojournalism
Photojournalism is a particular form of photography (the collecting,
editing, and presenting of news material for publication or broadcast)
that employs images in order to tell a news story. It is now usually
understood to refer only to still images, but in some cases the term
also refers to video used in broadcast journalism. Photojournalism is
distinguished from other close branches of photography (e.g.,
documentary photography, social documentary photography, street photography or celebrity photography)
by complying with a rigid ethical framework which demands that the work
be both honest and impartial whilst telling the story in strictly
journalistic terms. Photojournalists create pictures that contribute to
the news media, and help communities connect with one other. Photojournalists must be well informed and knowledgeable about events
happening right outside their door. They deliver news in a creative
format that is not only informative, but also entertaining.
The camera has a long and distinguished history as a means of
recording scientific phenomena from the first use by Daguerre and
Fox-Talbot, such as astronomical events (eclipses for example), small creatures and plants when the camera was attached to the eyepiece of microscopes (in photomicroscopy) and for macro photography of larger specimens. The camera also proved useful in recording crime scenes and the scenes of accidents, such as the Wootton bridge collapse in 1861. The methods used in analysing photographs for use in legal cases are collectively known as forensic photography. Crime scene photos are taken from three vantage point. The vantage points are overview, mid-range, and close-up.
In 1845 Francis Ronalds, the Honorary Director of the Kew Observatory,
invented the first successful camera to make continuous recordings of
meteorological and geomagnetic parameters. Different machines produced
12- or 24- hour photographic traces of the minute-by-minute variations
of atmospheric pressure, temperature, humidity, atmospheric electricity, and the three components of geomagnetic forces.
The cameras were supplied to numerous observatories around the world
and some remained in use until well into the 20th century. Charles Brooke a little later developed similar instruments for the Greenwich Observatory.
Science uses image technology that has derived from the design of
the Pin Hole camera. X-Ray machines are similar in design to Pin Hole
cameras with high-grade filters and laser radiation.[48]
Photography has become universal in recording events and data in science and engineering, and at crime scenes or accident scenes. The method has been much extended by using other wavelengths, such as infrared photography and ultraviolet photography, as well as spectroscopy. Those methods were first used in the Victorian era and improved much further since that time.
The first photographed atom was discovered in 2012 by physicists
at Griffith University, Australia. They used an electric field to trap
an "Ion" of the element, Ytterbium. The image was recorded on a CCD, an
electronic photographic film.
Social and cultural implications
Photography may be used both to capture reality and to produce a work of art. While photo manipulation was often frowned upon at first, it was eventually used to great extent to produce artistic effects. Nude composition 19 from 1988 by Jaan Künnap.
There are many ongoing questions about different aspects of photography. In her writing "On Photography" (1977), Susan Sontag discusses concerns about the objectivity of photography. This is a highly debated subject within the photographic community.
Sontag argues, "To photograph is to appropriate the thing photographed.
It means putting one's self into a certain relation to the world that
feels like knowledge, and therefore like power."
Photographers decide what to take a photo of, what elements to exclude
and what angle to frame the photo, and these factors may reflect a
particular socio-historical context. Along these lines, it can be argued
that photography is a subjective form of representation.
Modern photography has raised a number of concerns on its effect on society. In Alfred Hitchcock's Rear Window
(1954), the camera is presented as promoting voyeurism. 'Although the
camera is an observation station, the act of photographing is more than
passive observing'.
The camera doesn't rape or even possess, though it may presume,
intrude, trespass, distort, exploit, and, at the farthest reach of
metaphor, assassinate – all activities that, unlike the sexual push and
shove, can be conducted from a distance, and with some detachment.
Digital imaging has raised ethical concerns because of the ease of
manipulating digital photographs in post-processing. Many
photojournalists have declared they will not crop their pictures or are forbidden from combining elements of multiple photos to make "photomontages", passing them as "real" photographs. Today's technology has made image editing
relatively simple for even the novice photographer. However, recent
changes of in-camera processing allow digital fingerprinting of photos
to detect tampering for purposes of forensic photography.
Photography is one of the new media forms that changes perception and changes the structure of society.
Further unease has been caused around cameras in regards to
desensitization. Fears that disturbing or explicit images are widely
accessible to children and society at large have been raised.
Particularly, photos of war and pornography are causing a stir. Sontag
is concerned that "to photograph is to turn people into objects that can
be symbolically possessed." Desensitization discussion goes hand in
hand with debates about censored images. Sontag writes of her concern
that the ability to censor pictures means the photographer has the
ability to construct reality.
One of the practices through which photography constitutes
society is tourism. Tourism and photography combine to create a "tourist
gaze"
in which local inhabitants are positioned and defined by the camera
lens. However, it has also been argued that there exists a "reverse
gaze" through which indigenous photographees can position the tourist photographer as a shallow consumer of images.
Additionally, photography has been the topic of many songs in popular culture.
Law
Photography is both restricted as well as protected by the law in
many jurisdictions. Protection of photographs is typically achieved
through the granting of copyright or moral rights to the photographer. In the United States, photography is protected as a First Amendment right and anyone is free to photograph anything seen in public spaces as long as it is in plain view.
In the UK a recent law (Counter-Terrorism Act 2008) increases the power
of the police to prevent people, even press photographers, from taking
pictures in public places.
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20sec exposure photograph taken with a tripod mounted DSLR camera with 18-55mm lens
Fixed tripod mounted camera capturing "star trails"
Star trails photographed in earth orbit from the International Space Station
Fixed tripod image of a solar eclipse using a digital-SLR camera with a 500 mm lens
1 minute exposure using ISO 800 film, wide angle lens, piggybacked on an equatorial telescope
Comet Hale-Bopp, camera with a 300mm lens piggybacked
Image of the moon taken with a Nikon Coolpix P5000 digital camera via Afocal projection through an 8-inch Schmidt–Cassegrain telescope
The Moon photographed using the Afocal technique, using 10 seconds of video stacked to create a final image.
A composite of several Digital-SLR photos compiled in Photoshop taken via eyepiece projection from an 8-inch Schmidt Cassegrain telescope.
Saturn image using negative projection (Barlow lens) with a webcam attached to a 250mm Newtonian telescope. It is a composite images made from 10% of the best exposures out of 1200 images using freeware image stacking and sharpening software (Giotto)
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