"more important and dignified. Far-sighted or aging colonial Americans imported spectacles from Europe. Spectacles were primarily for the affluent and literate colonists, who required a valuable and precious appliance. Benjamin Franklin in the 1780s developed the bifocal. Bifocal lenses advanced little in the first half of the 19th century. The terms bifocal and trifocal were introduced in London by John Isaac Hawkins, whose trifocals were patented in 1827. In 1884 B. M. Hanna was granted patents on two forms of bifocals which become commercially standardized as the ""cemented"" and ""perfection"" bifocals. Both had the serious faults of ugly appearance, fragility,"
"independently by more than one person, it is possible that the invention of bifocals may have been such a case. John Isaac Hawkins, the inventor of trifocal lenses, coined the term ""bifocals"" in 1824 and credited Dr. Franklin. In 1955, Irving Rips of Younger Optics created the first seamless or ""invisible"" bifocal, a precursor to all progressive lenses. Construction Original bifocals were designed with the most convex lenses (for close viewing) in the lower half of the frame and the least convex lenses on the upper. Up until the beginning of the 20th century two separate lenses were cut in"
"half and combined together in the rim of the frame. The mounting of two half lenses into a single frame led to a number of early complications and rendered such spectacles quite fragile. A method for fusing the sections of the lenses together was developed by Louis de Wecker at the end of the 19th century and patented by Dr. John L. Borsch, Jr. in 1908. Today most bifocals are created by molding a reading segment into a primary lens and are available with the reading segments in a variety of shapes and sizes. The most popular is the D-segment,"
"Augustin-Jean Fresnel Augustin-Jean Fresnel ( , ; ; 10 May 178814 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular theory, from the late 1830s until the end of the 19th century. But he is perhaps better known for inventing the catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of ""stepped"" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler dioptric (purely refractive) stepped lens, first proposed by Count Buffon and independently"
"a flint lens.” Up to the present day, Erfle's patents have continued to be cited in later patent applications by other scientists. Heinrich Erfle Heinrich Erfle (April 1, 1884, Dürkheim – April 8, 1923, Jena) was a German optician who spent most of his career at Carl Zeiss. In 1917 he invented the first wide-field eyepieces for telescopes and binoculars. During his short life he developed a number of new designs for telescopes and eyepieces. Heinrich Erfle studied at the Ludwig-Maximilians-Universität and the Technical University of Munich (TUM), from which he graduated in 1907 with a thesis on ""Optical properties"
"Heinrich Erfle Heinrich Erfle (April 1, 1884, Dürkheim – April 8, 1923, Jena) was a German optician who spent most of his career at Carl Zeiss. In 1917 he invented the first wide-field eyepieces for telescopes and binoculars. During his short life he developed a number of new designs for telescopes and eyepieces. Heinrich Erfle studied at the Ludwig-Maximilians-Universität and the Technical University of Munich (TUM), from which he graduated in 1907 with a thesis on ""Optical properties and electron theory."" His dissertation advisers were Wilhelm Ebert and Sebastian Finsterwalder. After a two-year residency at the TUM he began to"
"name of the ancient Greek astronomer Hipparchus, who is considered the founder of trigonometry and the discoverer of the precession of the equinoxes (due to the Earth wobbling on its axis). The spacecraft carried a single all-reflective, eccentric Schmidt telescope, with an aperture of . A special beam-combining mirror superimposed two fields of view, 58 degrees apart, into the common focal plane. This complex mirror consisted of two mirrors tilted in opposite directions, each occupying half of the rectangular entrance pupil, and providing an unvignetted field of view of about 1°×1°. The telescope used a system of grids, at the"
"Joseph von Fraunhofer Joseph Ritter von Fraunhofer (; ; 6 March 1787 – 7 June 1826) was a Bavarian physicist and optical lens manufacturer. He made optical glass and achromatic telescope objective lenses, invented the spectroscope, and developed diffraction grating. In 1814, he discovered and studied the dark absorption lines in the spectrum of the sun now known as Fraunhofer lines. The German research organization Fraunhofer Society is named after him and is Europe's biggest Society for the Advancement of Applied Research. Joseph Fraunhofer was born in Straubing, in the Electorate of Bavaria, to Franz Xaver Fraunhofer and Maria Anna"
"Binoculars Binoculars or field glasses are two telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal mounted military models. Unlike a (monocular) telescope, binoculars give users a three-dimensional image: for nearer objects the two views, presented to each of the viewer's eyes from slightly different viewpoints, produce a merged view with an impression of depth. Almost from the invention of the telescope in the 17th century"
"Salvino degli Armati. Around 1733, Scarlett was commissioned by Chester Moor Hall, the inventor of color-pure lenses, to produce a partial lens of the first Achromaten. However, he passed this order on to George Bass. He had also received the subcontract for the other lens part and recognized the color purity of the double lens. So Bass could later pass on the mystery of the Achromaten to John Dollond, who received the patent for their production in 1758. Edward Scarlett Edward Scarlett (1688 - 1743 in London) was an English optician and instrument maker, who first invented an eyeglass frame"
"John Adams Whipple John Adams Whipple (September 10, 1822 – April 10, 1891) was an American inventor and early photographer. He was the first in the United States to manufacture the chemicals used for daguerreotypes; he pioneered astronomical and night photography; he was a prize-winner for his extraordinary early photographs of the moon; and he was the first to produce images of stars other than the sun (the star Vega and the Mizar-Alcor stellar sextuple system, which was thought to be a double star until 2009. Whipple was born in Grafton, Massachusetts, to Jonathan and Melinda (Grout) Whipple. While a"
"Trifocal lenses Trifocals are eyeglasses with lenses that have three regions which correct for distance, intermediate (arm's length), and near vision. John Isaac Hawkins developed the trifocal lens in 1827. Trifocals are mostly used by people with advanced presbyopia who have been prescribed 2 diopters or more of reading addition. The intermediate addition is normally half the reading addition. So, for someone with a distance prescription of −4 diopters and a reading addition of +3, the reading portion of their trifocals would have a net power of −1, and the intermediate segment would be −2.5 diopters. Trifocal lenses are made"
"prism binoculars"" are named after Italian optician Ignazio Porro who patented this image erecting system in 1854, which was later refined by makers like the Carl Zeiss company in the 1890s. Binoculars of this type use a pair of Porro prisms in a Z-shaped configuration to erect the image. This results in binoculars that are wide, with objective lenses that are well separated and offset from the eyepieces, giving a better sensation of depth. Porro prism designs have the added benefit of folding the optical path so that the physical length of the binoculars is less than the focal length"
"Hans-Joachim Haase (optician) Hans-Joachim Haase (1915 – December 20, 2001) was a German clockmaker, optician and inventor, who became known for an apparatus for testing binocular vision and for the ""MKH method"", an alternative method intended to improve binocular vision using corrective lenses. This method, which is controversial, has mainly found application in German-speaking countries. Born the son of an optician, Haase underwent formal training to be a clockmaker and an optician, and became a ""Meister""-optician in 1951. From 1953 onwards he held a teaching position at the """" (SFOF) in Berlin. With an acute interest in binocular vision, Haase"
"0.5 m to 30 m, depending upon the design of the binoculars. If the close focus distance is short respect to the magnification, the binocular can be used also to see particulars not visible to the naked eye. Binocular eyepieces usually consist of three or more lens elements in two or more groups. The lens furthest from the viewer's eye is called the ""field lens"" and that closest to the eye the ""eye lens"". The most common configuration is that invented in 1849 by Carl Kellner. In this arrangement, the eye lens is a plano-concave/ double convex achromatic doublet (the"
"biconvex, and there is a biconcave element between them. The Plasmat lens is made in many variants, e.g. departing from exact symmetry, adding a lens to one or both groups, or separating the innermost or outermost element from the rest of the group. Standard lenses for large-format cameras are generally of the Plasmat type, as are many macro lenses. Convertible lenses for large-format photography often consist of Plasmat cells. Plasmat lens The Plasmat lens is a widely used and long-established lens type invented by Paul Rudolph in 1918, especially common in large-format photography. It provides high correction of aberrations with"
"the Hungarian Academy of Sciences in 1873. Petzval is considered to be one of the main founders of geometrical optics, modern photography and cinematography. Among his inventions are the Petzval portrait lens and opera glasses, both still in common use today. He is also credited with the discovery of the Laplace transform and is also known for his extensive work on aberration in optical systems. In 1801, Joseph Petzval's father married the Zipser-German Zuzana Kreutzmann, who was born in Szepesbéla, Kingdom of Hungary, a daughter of the previous teacher at the same school in Zipser Bela. The couple brought up"
"be visible over greater distances. The idea of creating a thinner, lighter lens in the form of a series of annular steps is often attributed to Georges-Louis Leclerc, Comte de Buffon. Whereas Buffon proposed grinding such a lens from a single piece of glass, the Marquis de Condorcet (1743–1794) proposed making it with separate sections mounted in a frame. French physicist and engineer Augustin-Jean Fresnel is most often given credit for the development of the multi-part lens for use in lighthouses. According to ""Smithsonian"" magazine, the first Fresnel lens was used in 1823 in the Cordouan lighthouse at the mouth"
"eyepieces consist of two plano-convex lenses with the plane sides towards the eye separated by an air gap. The lenses are called the eye lens and the field lens. The focal plane is located between the two lenses. It was invented by Christiaan Huygens in the late 1660s and was the first compound (multi-lens) eyepiece. Huygens discovered that two air spaced lenses can be used to make an eyepiece with zero transverse chromatic aberration. If the lenses are made of glass of the same refractive index, to be used with a relaxed eye and a telescope with an infinitely distant"
"of Santa Maria Maggiore. In the twentieth century, efforts were made to expose as a hoax the claim that Salvino degli Armati invented eyeglasses: The ""Dizionario enciclopedico italiano"" (1955), vol. 1, lists Salvino degli Armati together with an exposure of del Migliore's false claim. Furthermore, Vasco Ronchi (1897-1988), an Italian physicist who specialized in optics, also published an article on the subject as did the American historian of science Edward Rosen (1906-1985) and the Italian professor of ophthamology Giuseppe Albertotti (1851-1936). Salvino D'Armati Salvino D'Armato degli Armati of Florence (died 1317) is sometimes credited with the invention of eyeglasses, however"
"Edward Scarlett Edward Scarlett (1688 - 1743 in London) was an English optician and instrument maker, who first invented an eyeglass frame with earhooks in 1727. This frame is held by the nose and ears, at times the glasses were called in contrast to the nasal cannula and ""temples"" because they had short straps that pressed on the temple. Among other things, Scarlett made polemoscopes (optical instruments that could be seen over obstacles) and tried not only to limit them to military use, but also to expel them. The lenses themselves were not, as often claimed, invented in 1285 by"
"David Brewster Sir David Brewster (11 December 178110 February 1868) was a British scientist, inventor, author, and academic administrator. In science he is principally remembered for his experimental work in physical optics, mostly concerned with the study of the polarization of light and including the discovery of Brewster's angle. He studied the birefringence of crystals under compression and discovered photoelasticity, thereby creating the field of optical mineralogy. For this work, William Whewell dubbed him the ""father of modern experimental optics"" and ""the Johannes Kepler of optics."" A pioneer in photography, Brewster invented an improved stereoscope, which he called ""lenticular stereoscope"""
"John Herschel Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath, mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint, and did botanical work. Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays; his ""Preliminary Discourse"" (1831), which advocated an inductive approach to scientific experiment and theory building, was an important contribution to the philosophy of"
"2013, Thales Angénieux organizes every year on the occasion of the Cannes Film Festival the Pierre Angénieux Excellens in Cinematography ceremony to pay tribute to a prominent Director of Photography for its career. Pierre Angénieux Pierre Angénieux () (14 July 1907 in Saint-Héand – 26 June 1998) was a French engineer and optician, one of the inventors of the modern zoom lenses, and famous for introducing the Angénieux retrofocus. Angénieux graduated from the École nationale supérieure d'arts et métiers in 1928, and from the École supérieure d'optique the next year. He was a student of Henri Chrétien. After working for"
"Salvino D'Armati Salvino D'Armato degli Armati of Florence (died 1317) is sometimes credited with the invention of eyeglasses, however this claim was shown to be a hoax. The earliest mention of Salvino degli Armati as the inventor of eyeglasses occurred in 1684. Ferdinando Leopoldo del Migliore (1628-1696) of Florence published a book, ""Firenze citta' noblissima illustrata"" (""Florence, Most Noble City, illustrated""). In this book, del Migliore claimed to own a burial register of the Church of Santa Maria Maggiore, which had recently been renovated. This register supposedly recorded Armati's epitaph as follows: ""Original"" : ""Qui diace Salvino d'Armato degl' Armati"
"was first described by Vitruvius around 27 and 23 BC, although the actual inventor may have been Archimedes of Syracuse (c. 287 BC – c. 212 BC) during the First Punic War. Hero of Alexandria (10 AD - 70 AD) describes a similar device in chapter 34 of his ""Dioptra"". The machine was also used in the time of Roman Emperor Commodus (c. 192 AD), although after this point in time there seems to be a gap between its use in Roman times and that of the 15th century in Western Europe. Some researchers have speculated that the device might"
"traced back to 1895, when Paul Rudolph of Carl Zeiss Jena used cemented doublets as the central lenses to correct for chromatic aberration. Later the design was developed with additional glasses to give high-performance lenses of wide aperture. The main development was due to Taylor Hobson in the 1920s, resulting in the f/2.0 Opic and later the Speed Panchro designs, which were licensed to various other manufacturers. The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to with"
"idea of creating a thinner, lighter lens by making it with separate sections mounted in a frame is often attributed to Georges-Louis Leclerc, Comte de Buffon. The marquis de Condorcet (1743–1794) proposed grinding such a lens from a single thin piece of glass. However, it was the French physicist and engineer Augustin-Jean Fresnel who is credited with the development of the multi-part Fresnel lens for use in lighthouses. His design allowed for the construction of lenses of large aperture and short focal length, without the mass and volume of material that would be required by a lens of conventional design."
"inventions, and discoveries. Below is a list of publications he authored including many links to the scanned Google Books pages. Ernst Abbe Ernst Karl Abbe HonFRMS (23 January 1840 – 14 January 1905) was a German physicist, optical scientist, entrepreneur, and social reformer. Together with Otto Schott and Carl Zeiss, he laid the foundation of modern optics. Abbe developed numerous optical instruments. He was a co-owner of Carl Zeiss AG, a German manufacturer of research microscopes, astronomical telescopes, planetariums and other optical systems. Abbe was born 23 January 1840 in Eisenach, Saxe-Weimar-Eisenach, to Georg Adam Abbe and Elisabeth Christina Barchfeldt."
"Dipleidoscope A dipleidoscope is an instrument used to determine true noon, its name comes from the Greek for ""double image viewer"". It consists of a small telescope and a prism that creates a double image of the sun. When the two images overlap, it is local true noon. The instrument is capable of determining true noon to within ten seconds. The dipleidoscope was invented by Giovanni Battista Amici in the first half of the 19th century. Edward John Dent, a chronometer and clockmaker in London, was working in the 1830s on a simple contrivance that would allow the public to"
"Joseph Dixon (inventor) Joseph Dixon (1799–1869) was an inventor, entrepreneur and the founder of what became the Dixon Ticonderoga Company, a well-known manufacturer of pencils in the United States. His fascination with new technologies led to many innovations such as a mirror for a camera that was the forerunner of the viewfinder, a patented double-crank steam engine, and a method of printing banknotes to thwart counterfeiters. Most notably, Dixon manufactured the first wood and graphite pencil in the country. Among his associates were such American inventors as Robert Fulton, Samuel Morse, and Alexander Graham Bell, and politician/business partner Orestes Cleveland."
"George Dollond George Dollond (10 June 1774 – 30 November 1852) was an English optician who constructed optical precision instruments used in astronomy, geodesy and also in navigation. Together with Peter Barlow, he also invented an afocal system to extend the focal length of telescopes, called the Barlow lens. He was born in London, the nephew of the famous optician Peter Dollond. He was the son of John Dollond's daughter, Susan (or Susanne) (1728–1798) who married William Huggins. His father died when he was a child. When George Huggins went into partnership with Peter Dollond in 1805, he changed his"
"Hippolyte Bayard Hippolyte Bayard (20 January 1801 – 14 May 1887) was a French photographer and pioneer in the history of photography. He invented his own process that produced direct positive paper prints in the camera and presented the world's first public exhibition of photographs on 24 June 1839. He claimed to have invented photography earlier than Louis-Jacques Mandé Daguerre in France and William Henry Fox Talbot in England, the men traditionally credited with its invention. Bayard experimented with the new medium taking photos of plant speciments, statuary (including posing with them for self-portraits), street scenes, urban landscapes, architectural photos,"