In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. Objectives can be combinations of several optical elements, they are used in microscopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are called object lenses, object glasses, or objective glasses; the objective lens of a microscope is the one at the bottom near the sample. At its simplest, it is a high-powered magnifying glass, with short focal length; this is brought close to the specimen being examined so that the light from the specimen comes to a focus inside the microscope tube. The objective itself is a cylinder containing one or more lenses that are made of glass. Microscope objectives are characterized by two parameters: numerical aperture; the magnification ranges from 4× to 100×. It is combined with the magnification of the eyepiece to determine the overall magnification of the microscope.
Numerical aperture for microscope lenses ranges from 0.10 to 1.25, corresponding to focal lengths of about 40 mm to 2 mm, respectively. A typical microscope has three or four objective lenses with different magnifications, screwed into a circular "nosepiece" which may be rotated to select the required lens; these lenses are color coded for easier use. The least powerful lens is called the scanning objective lens, is a 4× objective; the second lens is referred to as the small objective lens and is a 10× lens. The most powerful lens out of the three is referred to as the large objective lens and is 40–100×; some microscopes use an oil-immersion or water-immersion lens, which can have magnification greater than 100, numerical aperture greater than 1. These objectives are specially designed for use with refractive index matching oil or water, which must fill the gap between the front element and the object; these lenses give greater resolution at high magnification. Numerical apertures as high as 1.6 can be achieved with oil immersion.
Camera lenses need to cover a large focal plane so are made up of a number of optical lens elements to correct optical aberrations. Image projectors use objective lenses that reverse the function of a camera lens, with lenses designed to cover a large image plane and project it at a distance onto another surface. In a telescope the objective is the lens at the front end of a refractor or the image-forming primary mirror of a reflecting or catadioptric telescope. A telescope's light-gathering power and angular resolution are both directly related to the diameter of its objective lens or mirror; the larger the objective, the dimmer the object it can view and the more detail it can resolve. List of telescope parts and construction
A film called a movie, motion picture, moving picture, or photoplay, is a series of still images that, when shown on a screen, create the illusion of moving images. This optical illusion causes the audience to perceive continuous motion between separate objects viewed in rapid succession; the process of filmmaking is both an industry. A film is created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, other visual effects; the word "cinema", short for cinematography, is used to refer to filmmaking and the film industry, to the art of filmmaking itself. The contemporary definition of cinema is the art of simulating experiences to communicate ideas, perceptions, beauty or atmosphere by the means of recorded or programmed moving images along with other sensory stimulations. Films were recorded onto plastic film through a photochemical process and shown through a movie projector onto a large screen.
Contemporary films are now fully digital through the entire process of production and exhibition, while films recorded in a photochemical form traditionally included an analogous optical soundtrack. Films are cultural artifacts created by specific cultures, they reflect those cultures. Film is considered to be an important art form, a source of popular entertainment, a powerful medium for educating—or indoctrinating—citizens; the visual basis of film gives it a universal power of communication. Some films have become popular worldwide attractions through the use of dubbing or subtitles to translate the dialog into other languages; the individual images that make up a film are called frames. In the projection of traditional celluloid films, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after its source disappears.
The perception of motion is due to a psychological effect called the phi phenomenon. The name "film" originates from the fact that photographic film has been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, including picture, picture show, moving picture and flick; the most common term in the United States is movie. Common terms for the field in general include the big screen, the silver screen, the movies, cinema. In early years, the word sheet was sometimes used instead of screen. Preceding film in origin by thousands of years, early plays and dances had elements common to film: scripts, costumes, direction, audiences and scores. Much terminology used in film theory and criticism apply, such as mise en scène. Owing to the lack of any technology for doing so, the moving images and sounds could not be recorded for replaying as with film; the magic lantern created by Christiaan Huygens in the 1650s, could be used to project animation, achieved by various types of mechanical slides.
Two glass slides, one with the stationary part of the picture and the other with the part, to move, would be placed one on top of the other and projected together the moving slide would be hand-operated, either directly or by means of a lever or other mechanism. Chromotrope slides, which produced eye-dazzling displays of continuously cycling abstract geometrical patterns and colors, were operated by means of a small crank and pulley wheel that rotated a glass disc. In the mid-19th century, inventions such as Joseph Plateau's phenakistoscope and the zoetrope demonstrated that a designed sequence of drawings, showing phases of the changing appearance of objects in motion, would appear to show the objects moving if they were displayed one after the other at a sufficiently rapid rate; these devices relied on the phenomenon of persistence of vision to make the display appear continuous though the observer's view was blocked as each drawing rotated into the location where its predecessor had just been glimpsed.
Each sequence was limited to a small number of drawings twelve, so it could only show endlessly repeating cyclical motions. By the late 1880s, the last major device of this type, the praxinoscope, had been elaborated into a form that employed a long coiled band containing hundreds of images painted on glass and used the elements of a magic lantern to project them onto a screen; the use of sequences of photographs in such devices was limited to a few experiments with subjects photographed in a series of poses because the available emulsions were not sensitive enough to allow the short exposures needed to photograph subjects that were moving. The sensitivity was improved and in the late 1870s, Eadweard Muybridge created the first animated image sequences photographed in real-time. A row of cameras was used, each, in turn, capturing one image on a photographic glass plate, so the total number of images in each sequence was limited by the number of cameras, about two dozen at most. Muybridge used his system to analyze the movements of a wi
Dissolving views were a popular type of 19th century magic lantern show exhibiting the gradual transition from one projected image to another. The effect is similar to a dissolve in modern filmmaking. Typical examples had landscapes that dissolved from day from summer to winter; the effect was achieved by aligning the projection of two matching images and diminishing the first image while introducing the second image. The subject and the effect of magic lantern dissolving views is similar to the popular Diorama theatre paintings which originated in Paris in 1822; the terms "dissolving views", "dioramic views", or "diorama" were used interchangeably in 19th century magic lantern playbills. While most dissolving views showed landscapes or architecture in different light, the effect was used in other ways. For instance, Henry Langdon Childe showed groves changing into cathedrals. Another popular example has a soldier sleeping or daydreaming on the battlefield, with dissolving views displaying several of his dreams about home above his head.
The dissolve effect was invented by phantasmagoria pioneer Paul de Philipsthal while in Ireland in 1804. He thought of using two lanterns to make the spirit of Samuel appear out of a mist in his representation of the Witch of Endor. While working out the desired effect, he got the idea of using the technique with landscapes. Information about De Philipsthal's activities after 1804 is limited, so it remains unclear whether he did incorporate the effect in his shows before other lanternists developed their own versions. Surviving playbills of his shows seem to focus on the exhibition of automata, besides "experiments in optics, aeronautics and pyrotechnics"; some bills do not mention any optical effects. However, an 1812 newspaper about a London performance indicates that De Philipsthal presented "a series of landscapes, which insensibly change to various scenes producing a magical effect". After a few other lanternists had presented similar shows, De Philipsthal returned from retirement in December 1827 with a show that included "various splendid views transforming themselves imperceptibly from one form into another".
Another possible inventor is Henry Langdon Childe. He is said to have invented the dissolving views in 1807 and to have improved and completed the technique in 1818. However, there's no documentation of Childe performing with a magic lantern before 1827; that year he presented "Scenic Views, showing the various effects of light and shade" with a series of subjects that would become classics in many dissolving view shows, while some had been subjects in the London Diorama the years before. In 1826 Scottish magician and ventriloquist M. Henry's introduced what he referred to as "Beautiful Dissolvent Scenes", "imperceptibly changing views", "dissolvent views" and "Magic Views" which were created "by Machinery invented by M. Henry"; the oldest known use of the term "dissolving views" occurs on playbills for Childe's shows at the Adelphi Theatre in London in 1837. Childe further popularized the dissolving views at the Royal Polytechnic Institution in the early 1840s. Biunial lanterns, with two projecting optical sets in one apparatus, were produced to more project dissolving views.
The first biunial lantern, dubbed the "Biscenascope" was made by the optician Mr. Clarke and presented at the Royal Adelaide Gallery in London on December 5, 1840. On triple lanterns enabled the addition of more effects, for instance the effect of snow falling while a green landscape dissolves into a snowy winter version. A mechanical device could be fitted on the magic lantern, which locked up a diaphragm on the first slide whilst a diaphragm on a second slide was opened simultaneously. Philip Carpenter's copper-plate printing process, introduced in 1823, may have made it much easier to create duplicate slides with printed outlines that could be colored differently to create dissolving view slides. However, all early dissolving view slides seem to have been hand-painted
A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image. A typical stereoscope provides each eye with a lens that makes the image seen through it appear larger and more distant and also shifts its apparent horizontal position, so that for a person with normal binocular depth perception the edges of the two images fuse into one "stereo window". In current practice, the images are prepared so that the scene appears to be beyond this virtual window, through which objects are sometimes allowed to protrude, but this was not always the custom. A divider or other view-limiting feature is provided to prevent each eye from being distracted by seeing the image intended for the other eye. Most people can, with practice and some effort, view stereoscopic image pairs in 3D without the aid of a stereoscope, but the physiological depth cues resulting from the unnatural combination of eye convergence and focus required will be unlike those experienced when viewing the scene in reality, making an accurate simulation of the natural viewing experience impossible and tending to cause eye strain and fatigue.
Although more recent devices such as Realist-format 3D slide viewers and the View-Master are stereoscopes, the word is now most associated with viewers designed for the standard-format stereo cards that enjoyed several waves of popularity from the 1850s to the 1930s as a home entertainment medium. Devices such as polarized and shutter glasses which are used to view two superimposed or intermingled images, rather than two physically separate images, are not categorized as stereoscopes; the earliest type of stereoscope was invented by Sir Charles Wheatstone in 1838. It used a pair of mirrors at 45 degree angles to the user's eyes, each reflecting a picture located off to the side, it demonstrated the importance of binocular depth perception by showing that when two pictures simulating left-eye and right-eye views of the same object are presented so that each eye sees only the image designed for it, but in the same location, the brain will fuse the two and accept them as a view of one solid three-dimensional object.
Wheatstone's stereoscope was introduced in the year before the first practical photographic process became available, so drawings were used. This type of stereoscope has the advantage that the two pictures can be large if desired. Contrary to a common assertion, David Brewster did not invent the stereoscope, as he himself was at pains to make clear. A rival of Wheatstone, Brewster credited the invention of the device to a Mr. Elliot, a "Teacher of Mathematics" from Edinburgh, according to Brewster, conceived of the idea as early as 1823 and, in 1839, constructed "a simple stereoscope without lenses or mirrors", consisting of a wooden box 18 inches long, 7 inches wide and 4 inches high, used to view drawn landscape transparencies, since photography had yet to be invented. Brewster's personal contribution was the suggestion to use lenses for uniting the dissimilar pictures in 1849; this allowed a reduction in size, creating hand-held devices, which became known as Brewster Stereoscopes, much admired by Queen Victoria when they were demonstrated at the Great Exhibition of 1851.
Brewster was unable to find in Britain an instrument maker capable of working with his design, so he took it to France, where the stereoscope was improved by Jules Duboscq who made stereoscopes and stereoscopic daguerreotypes, a famous picture of Queen Victoria, displayed at The Great Exhibition. Overnight a 3D industry developed and 250,000 stereoscopes were produced and a great number of stereoviews, stereo cards, stereo pairs or stereographs were sold in a short time. Stereographers were sent throughout the world to capture views for the new medium and feed the demand for 3D. Cards were printed with these views with explanatory text when the cards were looked at through the double-lensed viewer, sometimes called a stereopticon, a common misnomer. In 1861 Oliver Wendell Holmes created and deliberately did not patent a handheld, much more economical viewer than had been available before; the stereoscope, which dates from the 1850s, consisted of two prismatic lenses and a wooden stand to hold the stereo card.
This type of stereoscope remained in production for a century and there are still companies making them in limited production currently. In the mid-20th century the View-Master stereoscope, with its rotating cardboard disks containing image pairs, was popular first for'virtual tourism' and as a toy. In 2010, Hasbro started producing a stereoscope designed to hold an iPhone or iPod Touch, called the My3D. In 2014, Google released. Apps on the mobile phone substitute for stereo cards; the underlying technology is otherwise unchanged from earlier stereoscopes. Several fine arts photographers and graphic artists have and continue to produce original artwork to be viewed using stereoscopes. A simple stereoscope is limited in the size of the image. A more complex stereoscope uses a pair of horizontal periscope-like devices, allowing the use of larger images that can present more detailed information in a wider field of view; the stereoscope is an instrument in which two photographs of the same object, taken from different angles, are presented, one to each eye.
This recreates the way which in natural vis
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University of California Press, otherwise known as UC Press, is a publishing house associated with the University of California that engages in academic publishing. It was founded in 1893 to publish books and papers for the faculty of the University of California, established 25 years earlier in 1868, its headquarters are located in California. The University of California Press publishes in the following general subject areas: anthropology, ancient world/classical studies and the West, cinema & media studies, environmental studies and wine, music, psychology, public health and medicine and sociology, it is a non-profit publishing arm of the University of California. Of its authors 25% are affiliated with the University of California, it publishes on average 175 new books and 30 multi-issue journals in the humanities, social sciences, natural sciences. It maintains 4,000 book titles in print, it is the publisher of Collabra and Luminos open access initiatives. The Press commissioned as its corporate typeface University of California Old Style from type designer Frederic Goudy from 1936-1938, although it no longer always uses the design.
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The Collabra program publishes two open access journals, Collabra: Psychology and Elementa: Science of the Anthropocene, with plans for continued expansion and journal acquisition. Luminos Luminos is University of California Press’s open access response to the challenged monograph landscape. With the same high standards for selection, peer review and marketing as its traditional book publishing program, Luminos is a transformative model, built as a partnership where costs and benefits are shared; the University of California Press re-printed a number of novels under the California Fiction series from 1996–2001. These titles were selected for their literary merit and for their illumination of California history and culture; the Ford by Mary Austin Thieves' Market by A. I. Bezzerides Disobedience by Michael Drinkard Words of My Roaring by Ernest J. Finney Skin Deep by Guy Garcia Fat City by Leonard Gardiner Chez Chance by Jay Gummerman Continental Drift by James D. Houston The Vineyard by Idwal Jones In the Heart of the Valley of Love by Cynthia Kadohata Always Coming Home by Ursula K.
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A slide projector is an opto-mechanical device for showing photographic slides. 35 mm slide projectors, direct descendants of the larger-format magic lantern, first came into widespread use during the 1950s as a form of occasional home entertainment. Reversal film was much in use, supplied slides snapped during vacations and at family events. Slide projectors were widely used in educational and other institutional settings. Photographic film slides and projectors have been replaced by image files on digital storage media shown on a projection screen by using a video projector or displayed on a large-screen video monitor. A continuous-slide lantern was patented in 1881, it included a dissolving-view apparatus. A projector has four main elements: electric incandescent light bulb or other light source reflector and "condensing" lens to direct the light to the slide slide holder focusing lensA flat piece of heat-absorbing glass is placed in the light path between the condensing lens and the slide, to avoid damaging the latter.
This glass absorbs infrared. Light passes through the transparent slide and lens, the resulting image is enlarged and projected onto a perpendicular flat screen so the audience can view its reflection. Alternatively, the image may be projected onto a translucent "rear projection" screen used for continuous automatic display for close viewing; this form of projection avoids the audience interrupting the light stream by casting their shadows on the projection or by bumping into the projector. Straight-tray slide projectors Round-tray slide projectors Stack-loader slide projectors Slide cube projectors Dual slide projectors Single slide projectors Dissolve projectors Viewer slide projectors Stereo slide projectors project two slides with different polarizations, making slides appear as three-dimensional to viewers wearing polarizing glasses Medium-format slide projectors Large-format slide projectors for use on stages, at large events, or for architectural and advertising installations where high light output is needed.
Overhead projectors List of known manufacturers of slide projectors: Agfa Gevaert, Germany → Reflecta Bauer, Germany → Bosch. Martin, Germany. Slide projectors get smarter all the time. Popular Mechanics. Retrieved 2011-10-22
The magic lantern known by its Latin name lanterna magica, is an early type of image projector employing pictures painted, printed or produced photographically on transparent plates, one or more lenses, a light source. It was developed in the 17th century and used for entertainment purposes, it was applied to educational purposes during the 19th century. Since the late 19th century smaller versions were mass-produced as a toy for children; the magic lantern was in wide use from the 18th century until the mid-20th century, when it was superseded by a compact version that could hold many 35 mm photographic slides: the slide projector. The magic lantern used a concave mirror in back of a light source to direct as much of the light as possible through a small rectangular sheet of glass—a "lantern slide"—on, the image to be projected, onward into a lens at the front of the apparatus; the lens was adjusted to optimally focus the plane of the slide at the distance of the projection screen, which could be a white wall, it therefore formed an enlarged image of the slide on the screen.
Some lanterns, including those of Christiaan Huygens and Jan van Musschenbroek, used 3 lenses. The pictures were hand painted on glass slides. Figures were rendered with black paint but soon transparent colors were used. Sometimes the painting was done on oiled paper. Black paint was used as a background to block superfluous light, so the figures could be projected without distracting borders or frames. Many slides were finished with a layer of transparent lacquer, but in a period cover glasses were used to protect the painted layer. Most hand-made slides were mounted in wood frames with a square opening for the picture. After 1820 the manufacturing of hand colored printed slides started making use of decalcomania transfers. Many manufactured slides were produced on strips of glass with several pictures on them and rimmed with a strip of glued paper; the first photographic lantern slides, called "Hyalotypes", were invented by the German-born brothers Ernst Wilhelm and Friedrich Langenheim in 1848 in Philadelphia and patented in 1850.
Apart from sunlight, the only light sources available at the time of invention in the 17th century were candles and oil lamps, which were inefficient and produced dim projected images. The invention of the Argand lamp in the 1790s helped to make the images brighter; the invention of limelight in the 1820s made them much brighter. The invention of the intensely bright electric arc lamp in the 1860s eliminated the need for combustible gases or hazardous chemicals, the incandescent electric lamp further improved safety and convenience, although not brightness. Several types of projection systems existed before the invention of the magic lantern. Giovanni Fontana, Leonardo Da Vinci and Cornelis Drebbel did describe and/or draw image projectors that may have been quite similar to the magic lantern. In the 17th century there was an immense interest in optics; the telescope and microscope were invented and apart from being useful to some scientists, such instruments were popular as entertaining curiosities with people who could afford them.
The magic lantern would prove to be a perfect successor. The magic lantern can be seen as a further development of camera obscura; this is a natural phenomenon that occurs when an image of a scene at the other side of a screen is projected through a small hole in that screen as an inverted image on a surface opposite to the opening. It was known at least since the 5th century BCE and experimented with in darkened rooms at least since circa 1000 CE; the use of a lens in the hole has been traced back to circa 1550. The portable camera obscura box with a lens was developed in the 17th century. Dutch inventor Cornelis Drebbel is thought to have sold one to Dutch poet and diplomat Constantijn Huygens in 1622, while the oldest known clear description of a box-type camera is in German Jesuit scientist Gaspar Schott's 1657 book Magia universalis naturæ et artis; the 1645 first edition of German Jesuit scholar Athanasius Kircher's book Ars Magna Lucis et Umbrae included a description of his invention, the "Steganographic Mirror": a primitive projection system with a focusing lens and text or pictures painted on a concave mirror reflecting sunlight intended for long distance communication.
He saw limitations in the increase of size and diminished clarity over a long distance and expressed his hope that someone would find a method to improve on this. In 1654 Belgian Jesuit mathematician André Tacquet used Kircher's technique to show the journey from China to Belgium of Italian Jesuit missionary Martino Martini, it is sometimes reported that Martini lectured throughout Europe with a magic lantern which he might have imported from China, but there's no evidence that anything other than Kircher's technique was used. However, Tacquet was a correspondent and friend of Christiaan Huygens and may thus have been a early adapter of the magic lantern technique that Huygens developed around this period. Prominent Dutch scientist Christiaan Huygens, is nowadays accepted as the true inventor of the magic lantern, he knew Athanasius Kircher's 1645 edition of Ars Magna Lucis et Umbrae which described a primitive projection system with a focusing lens and text or pictures painted on a concave mirror reflecting sunlight.
Christiaan's father Constantijn had been acquainted with Cornelis Drebbel who used some unidentified optical techniques to transform himself and summon wonderful appearances in magical performances. Constantijn Huygens wrote very