Gérard Corbasson Denis Suverran Philippe Parain
79-642: Angénieux is a French manufacturer of photographic and cinematographic lenses . The main markets are cinema, television, space travel and medicine. The company is part of the Thales Group , which represents Angénieux in 48 countries. The company is headquartered in Saint-Héand , near Saint-Étienne in France . Founded in 1935 by Pierre Angénieux , the company is established in Saint-Héand (Loire),
158-404: A patissier to amuse children. Régnier compared the mind of an old nagger with the lantern's effect of birds, monkeys, elephants, dogs, cats, hares, foxes and many strange beasts chasing each other. John Locke (1632-1704) referred to a similar device when wondering if ideas are formed in the human mind at regular intervals,"not much unlike the images in the inside of a lantern, turned round by
237-616: A Method of Copying Paintings upon Glass, and of Making Profiles, by the Agency of Light upon Nitrate of Silver. Invented by T. Wedgwood, Esq. With Observations by H. Davy in the first issue of the Journals of the Royal Institution of Great Britain . Swiss mathematician, physicist, astronomer, logician and engineer Leonhard Euler demonstrated an opaque projector , now commonly known as an episcope, around 1756. It could project
316-475: A UV coating to keep out the ultraviolet light that could taint color. Most modern optical cements for bonding glass elements also block UV light, negating the need for a UV filter. However, this leaves an avenue for lens fungus to attack if lenses are not cared for appropriately. UV photographers must go to great lengths to find lenses with no cement or coatings. A lens will most often have an aperture adjustment mechanism, usually an iris diaphragm , to regulate
395-408: A camera, or it might be interchangeable with lenses of different focal lengths , apertures , and other properties. While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be present in any lens system. It is the job of
474-511: A clear image of opaque images and (small) objects. French scientist Jacques Charles is thought to have invented the similar "megascope" in 1780. He used it for his lectures. Around 1872 Henry Morton used an opaque projector in demonstrations for huge audiences, for example in the Philadelphia Opera House which could seat 3500 people. His machine did not use a condenser or reflector, but used an oxyhydrogen lamp close to
553-463: 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, mostly 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. Kircher also suggested projecting live flies and shadow puppets from
632-406: A doublet (two elements) will often suffice. Some older cameras were fitted with convertible lenses (German: Satzobjektiv ) of normal focal length. The front element could be unscrewed, leaving a lens of twice the focal length, and half the angle of view and half the aperture. The simpler half-lens was of adequate quality for the narrow angle of view and small relative aperture. This would require
711-533: A further development of his own projection system. Although Athanasius Kircher claimed the Steganographic mirror as his own invention and wrote not to have read about anything like it, it has been suggested that Rembrandt's 1635 painting of " Belshazzar's Feast " depicts a steganographic mirror projection with God's hand writing Hebrew letters on a dusty mirror's surface. In 1654 Belgian Jesuit mathematician André Tacquet used Kircher's technique to show
790-508: A light source to project a clear magnified image of transparent objects. Fahrenheit's instrument may have been seen by German physician Johann Nathanael Lieberkühn who introduced the instrument in England, where optician John Cuff improved it with a stationary optical tube and an adjustable mirror. In 1774 English instrument maker Benjamin Martin introduced his "Opake Solar Microscope" for
869-547: A projection device, but can be seen as a first step in the development of projectors. It evolved into more refined forms of shadow puppetry in Asia, where it has a long history in Indonesia (records relating to Wayang since 840 CE), Malaysia, Thailand, Cambodia, China (records since around 1000 CE), India and Nepal. Projectors share a common history with cameras in the camera obscura . Camera obscura ( Latin for "dark room")
SECTION 10
#1732787572801948-434: A small army were placed on a wooden platform rotated by a cardboard propeller above a candle. The figures cast their shadows on translucent, oiled paper on the outside of the lantern. He suggested to take special care that the figures look lively: with horses raising their front legs as if they were jumping and soldiers with drawn swords, a dog chasing a hare, etcetera. According to Prevost barbers were skilled in this art and it
1027-461: A small closed box with a small hole, but it is unclear whether this actually was a projector or rather a type of show box with transparent pictures illuminated from behind and viewed through the hole. Leonardo da Vinci is thought to have had a projecting lantern - with a condensing lens, candle and chimney - based on a small sketch from around 1515. In his Three Books of Occult Philosophy (1531-1533) Heinrich Cornelius Agrippa claimed that it
1106-440: A specific form of multimedia or audio-visual production. Digital cameras had become commercialised by 1990, and in 1997 Microsoft PowerPoint was updated to include image files, accelerating the transition from 35 mm slides to digital images, and thus digital projectors, in pedagogy and training. Production of all Kodak Carousel slide projectors ceased in 2004, and in 2009 manufacture and processing of Kodachrome film
1185-509: A text by French author Jean de Meun in his part of Roman de la Rose (circa 1275). A theory known as the Hockney-Falco thesis claims that artists used either concave mirrors or refractive lenses to project images onto their canvas/board as a drawing/painting aid as early as circa 1430. It has also been thought that some encounters with spirits or gods since antiquity may have been conjured up with (concave) mirrors. Around 1420
1264-421: A toy for children. The light source in early opaque projectors was often limelight , with incandescent light bulbs and halogen lamps taking over later. Episcopes are still marketed as artists' enlargement tools to allow images to be traced on surfaces such as prepared canvas. In the late 1950s and early 1960s, overhead projectors began to be widely used in schools and businesses. The first overhead projector
1343-503: A transversely connected iron wire. The lamp would typically show images of horses and horse-riders. In France, similar lanterns were known as "lanterne vive" ( bright or living lantern ) in Medieval times. and as "lanterne tournante" since the 18th century. An early variation was described in 1584 by Jean Prevost in his small octavo book La Premiere partie des subtiles et plaisantes inventions . In his "lanterne", cut-out figures of
1422-412: A wider field of view than longer focal length lenses. A wider aperture, identified by a smaller f-number, allows using a faster shutter speed for the same exposure. The camera equation , or G#, is the ratio of the radiance reaching the camera sensor to the irradiance on the focal plane of the camera lens. The maximum usable aperture of a lens is specified as the focal ratio or f-number , defined as
1501-458: Is a hexagonal, cubical or round lantern which on the inside has cut-out silhouettes attached to a shaft with a paper vane impeller on top, rotated by heated air rising from a lamp. The silhouettes are projected on the thin paper sides of the lantern and appear to chase each other. Some versions showed some extra motion in the heads, feet and/or hands of figures by connecting them with a fine iron wire to an extra inner layer that would be triggered by
1580-399: Is a likely inventor of the microscope, is thought to have had some kind of projector that he used in magical performances. In a 1608 letter he described the many marvelous transformations he performed and the apparitions that he summoned by the means of his new invention based on optics. It included giants that rose from the earth and moved all their limbs very lifelike. The letter was found in
1659-485: Is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically . There is no major difference in principle between a lens used for a still camera , a video camera , a telescope , a microscope , or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to
SECTION 20
#17327875728011738-630: Is believed to be the Carl Zeiss Planar 50mm f/0.7 , which was designed and made specifically for the NASA Apollo lunar program to capture the far side of the Moon in 1966. Three of these lenses were purchased by filmmaker Stanley Kubrick in order to film scenes in his 1975 film Barry Lyndon , using candlelight as the sole light source. The complexity of a lens — the number of elements and their degree of asphericity — depends upon
1817-421: Is coated to reduce abrasion, flare , and surface reflectance , and to adjust color balance. To minimize aberration, the curvature is usually set so that the angle of incidence and the angle of refraction are equal. In a prime lens this is easy, but in a zoom there is always a compromise. The lens usually is focused by adjusting the distance from the lens assembly to the image plane, or by moving elements of
1896-439: Is generally used to image close-up very small subjects. A macro lens may be of any focal length, the actual focus length being determined by its practical use, considering magnification, the required ratio, access to the subject, and illumination considerations. It can be a special lens corrected optically for close up work or it can be any lens modified (with adapters or spacers, which are also known as "extension tubes".) to bring
1975-566: Is not true that all lenses with plastic elements are of low photographic quality. The 1951 USAF resolution test chart is one way to measure the resolving power of a lens. The quality of the material, coatings, and build affect the resolution. Lens resolution is ultimately limited by diffraction , and very few photographic lenses approach this resolution. Ones that do are called "diffraction limited" and are usually extremely expensive. Today, most lenses are multi-coated in order to minimize lens flare and other unwanted effects. Some lenses have
2054-458: Is notably known for having equipped a large part of portholes and windscreen of the US space program, from mercury to the space shuttle including Apollo (in particular Apollo 11) and Skylab. Available 12 models by focal length : 18, 21, 24, 28, 32, 40, 50, 60, 75, 100, 135, & 200 MM Camera lens A camera lens (also known as photographic lens or photographic objective )
2133-405: Is the different distances from which a subject can be framed, resulting in a different perspective . Photographs can be taken of a person stretching out a hand with a wideangle, a normal lens, and a telephoto, which contain exactly the same image size by changing the distance from the subject. But the perspective will be different. With the wideangle, the hands will be exaggeratedly large relative to
2212-419: Is the natural optical phenomenon that occurs when an image of a scene at the other side of a screen (or for instance a wall) is projected through a small hole in that screen to form an inverted image (left to right and upside down) on a surface opposite to the opening. The oldest known record of this principle is a description by Han Chinese philosopher Mozi (ca. 470 to ca. 391 BC). Mozi correctly asserted that
2291-555: The Pentax K mount are found across multiple brands, but this is not common today. A few mount designs, such as the Olympus/Kodak Four Thirds System mount for DSLRs, have also been licensed to other makers. Most large-format cameras take interchangeable lenses as well, which are usually mounted in a lensboard or on the front standard. The most common interchangeable lens mounts on the market today include
2370-515: The bellows had to be extended to twice the normal length. Good-quality lenses with maximum aperture no greater than f/2.8 and fixed, normal, focal length need at least three (triplet) or four elements (the trade name " Tessar " derives from the Greek tessera , meaning "four"). The widest-range zooms often have fifteen or more. The reflection of light at each of the many interfaces between different optical media (air, glass, plastic) seriously degraded
2449-679: The contrast and color saturation of early lenses, particularly zoom lenses, especially where the lens was directly illuminated by a light source. The introduction many years ago of optical coatings, and advances in coating technology over the years, have resulted in major improvements, and modern high-quality zoom lenses give images of quite acceptable contrast, although zoom lenses with many elements will transmit less light than lenses made with fewer elements (all other factors such as aperture, focal length, and coatings being equal). Many single-lens reflex cameras and some rangefinder cameras have detachable lenses. A few other types do as well, notably
Angénieux - Misplaced Pages Continue
2528-458: The 18th and 19th century. This popularity waned after the introduction of cinema in the 1890s. The magic lantern remained a common medium until slide projectors came into widespread use during the 1950s. A few years before his death in 1736 Polish-German-Dutch physicist Daniel Gabriel Fahrenheit reportedly constructed a solar microscope, which was a combination of the compound microscope with camera obscura projection. It needed bright sunlight as
2607-468: The 1970s to 1990s, purposed usually for marketing, promotion or community service or artistic displays, used 35mm and 46mm transparency slides ( diapositives ) projected by single or multiple slide projectors onto one or more screens in synchronization with an audio voice-over and/or music track controlled by a pulsed-signal tape or cassette. Multi-image productions are also known as multi-image slide presentations, slide shows and diaporamas and are
2686-420: The 1990s and early 2000s, but old analog projectors are still used at some places. The newest types of projectors are handheld projectors that use lasers or LEDs to project images. Movie theaters used a type of projector called a movie projector , nowadays mostly replaced with digital cinema video projectors. Projectors can be roughly divided into three categories, based on the type of input. Some of
2765-759: The Canon EF , EF-S and EF-M autofocus lens mounts. Others include the Nikon F manual and autofocus mounts, the Olympus / Kodak Four Thirds and Olympus/Panasonic Micro Four Thirds digital-only mounts, the Pentax K mount and autofocus variants, the Sony Alpha mount (derived from the Minolta mount) and the Sony E digital-only mount. A macro lens used in macro or "close-up" photography (not to be confused with
2844-518: The Chinese Han dynasty (206 BC – 24 AD) and are also found in Japan. The mirrors were cast in bronze with a pattern embossed at the back and a mercury amalgam laid over the polished front. The pattern on the back of the mirror is seen in a projection when light is reflected from the polished front onto a wall or other surface. No trace of the pattern can be discerned on the reflecting surface with
2923-468: The German Jesuit priest, physicist and astronomer Christoph Scheiner. From 1612 to at least 1630 Christoph Scheiner would keep on studying sunspots and constructing new telescopic solar projection systems. He called these "Heliotropii Telioscopici", later contracted to helioscope . The 1645 first edition of German Jesuit scholar Athanasius Kircher 's book Ars Magna Lucis et Umbrae included
3002-490: The Mamiya TLR cameras and SLR, medium format cameras ( RZ67 , RB67 , 645-1000s)other companies that produce medium format equipment such as Bronica, Hasselblad and Fuji have similar camera styles that allow interchangeability in the lenses as well, and mirrorless interchangeable-lens cameras . The lenses attach to the camera using a lens mount , which contains mechanical linkages and often also electrical contacts between
3081-452: The Sun as a light source powerful enough to expose the then available low-sensitivity photographic materials. It was superseded in the 1880s when other light sources, including the incandescent bulb , were developed for the darkroom enlarger and materials became ever more photo-sensitive. In the early and middle parts of the 20th century, low-cost opaque projectors were produced and marketed as
3160-486: The Venetian scholar and engineer Giovanni Fontana included a drawing of a person with a lantern projecting an image of a demon in his book about mechanical instruments "Bellicorum Instrumentorum Liber". The Latin text "Apparentia nocturna ad terrorem videntium" (Nocturnal appearance to frighten spectators)" clarifies its purpose, but the meaning of the undecipherable other lines is unclear. The lantern seems to simply have
3239-425: The amount of light that passes. In early camera models a rotating plate or slider with different sized holes was used. These Waterhouse stops may still be found on modern, specialized lenses. A shutter , to regulate the time during which light may pass, may be incorporated within the lens assembly (for better quality imagery), within the camera, or even, rarely, in front of the lens. Some cameras with leaf shutters in
Angénieux - Misplaced Pages Continue
3318-415: The angle of view, the maximum aperture, and intended price point, among other variables. An extreme wideangle lens of large aperture must be of very complex construction to correct for optical aberrations, which are worse at the edge of the field and when the edge of a large lens is used for image-forming. A long-focus lens of small aperture can be of very simple construction to attain comparable image quality:
3397-465: The aperture open until the instant of exposure to allow SLR cameras to focus with a brighter image with shallower depth of field, theoretically allowing better focus accuracy. Focal lengths are usually specified in millimetres (mm), but older lenses might be marked in centimetres (cm) or inches. For a given film or sensor size, specified by the length of the diagonal, a lens may be classified as a: A side effect of using lenses of different focal lengths
3476-410: The aperture, entrance pupil, and exit pupil are all in the same place because the only optical element is in the plane of the aperture, but in general these three will be in different places. Practical photographic lenses include more lens elements. The additional elements allow lens designers to reduce various aberrations, but the principle of operation remains the same: pencils of rays are collected at
3555-409: The axis of the lens, with rays striking the center of the lens passing straight through. The geometry is almost the same as with a simple pinhole lens, but rather than being illuminated by single rays of light, each image point is illuminated by a focused "pencil" of light rays . From the front of the camera, the small hole (the aperture), would be seen. The virtual image of the aperture as seen from
3634-597: The barrel or pressing a button which activates an electric motor . Commonly, the lens may zoom from moderate wide-angle, through normal, to moderate telephoto; or from normal to extreme telephoto. The zoom range is limited by manufacturing constraints; the ideal of a lens of large maximum aperture which will zoom from extreme wideangle to extreme telephoto is not attainable. Zoom lenses are widely used for small-format cameras of all types: still and cine cameras with fixed or interchangeable lenses. Bulk and price limit their use for larger film sizes. Motorized zoom lenses may also have
3713-572: The birthplace of its founder located near Saint-Étienne. His original specialty is the design and manufacture of precision optics for film and photography. Ousted from the amateur market in the 1960s, it refocused its activity on two productions that have made its reputation: spatial optics and zooms. Now part of the Thales Group, Thales Angénieux — since 2017 establishment of Thales Land & Air Systems — also designs, develops and produces military optics, mainly night vision binoculars. Angénieux
3792-423: The camera obscura image is inverted because light travels in straight lines. In the early 11th century, Arab physicist Ibn al-Haytham (Alhazen) described experiments with light through a small opening in a darkened room and realized that a smaller hole provided a sharper image. The oldest known objects that can project images are Chinese magic mirrors . The origins of these mirrors have been traced back to
3871-453: The compositional term close up ) is any lens that produces an image on the focal plane (i.e., film or a digital sensor) that is one quarter of life size (1:4) to the same size (1:1) as the subject being imaged. There is no official standard to define a macro lens, usually a prime lens , but a 1:1 ratio is, typically, considered "true" macro. Magnification from life size to larger is called "Micro" photography (2:1, 3:1 etc.). This configuration
3950-413: The enlarged projection of opaque objects. He claimed: The Opake Microsc[o]pe , not only magnifies the natural Appearance or Size of Objects of every Sort, but at the ſame time throws ſuch a Quantity of Solar Rays upon them, as to make all their Colours appear vaſtly more vivid and ſtrong than to the naked Eye; and their Parts ſo expanded and diſtinct upon a fixed Screen, that they are not only viewed with
4029-463: The entrance pupil and focused down from the exit pupil onto the image plane. A camera lens may be made from a number of elements: from one, as in the Box Brownie 's meniscus lens, to over 20 in the more complex zooms. These elements may themselves comprise a group of lenses cemented together. The front element is critical to the performance of the whole assembly. In all modern lenses the surface
SECTION 50
#17327875728014108-400: The focal plane "forward" for very close photography. Depending on the camera to subject distance and aperture, the depth-of-field can be very narrow, limiting the linear depth of the area that will be in focus. Lenses are usually stopped down to give a greater depth-of-field. Some lenses, called zoom lenses , have a focal length that varies as internal elements are moved, typically by rotating
4187-410: The focus, iris, and other functions motorized. Some notable photographic optical lens designs are: Image projector A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen . Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project
4266-479: The head. As the focal length increases, the emphasis on the outstretched hand decreases. However, if pictures are taken from the same distance, and enlarged and cropped to contain the same view, the pictures will have identical perspective. A moderate long-focus (telephoto) lens is often recommended for portraiture because the perspective corresponding to the longer shooting distance is considered to look more flattering. The widest aperture lens in history of photography
4345-476: The heat of a candle." Related constructions were commonly used as Christmas decorations in England and parts of Europe. A still relatively common type of rotating device that is closely related does not really involve light and shadows, but it simply uses candles and an impeller to rotate a ring with tiny figurines standing on top. Many modern electric versions of this type of lantern use all kinds of colorful transparent cellophane figures which are projected across
4424-505: The image directly, by using lasers . A virtual retinal display , or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen. The most common type of projector used today is called a video projector . Video projectors are digital replacements for earlier types of projectors such as slide projectors and overhead projectors . These earlier types of projectors were mostly replaced with digital video projectors throughout
4503-429: 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. By 1659 Dutch scientist Christiaan Huygens had developed the magic lantern, which used a concave mirror to reflect and direct as much of
4582-461: The lens and camera body. The lens mount design is an important issue for compatibility between cameras and lenses. There is no universal standard for lens mounts, and each major camera maker typically uses its own proprietary design, incompatible with other makers. A few older manual focus lens mount designs, such as the Leica M39 lens mount for rangefinders, M42 lens mount for early SLRs, and
4661-638: The lens assembly. To improve performance, some lenses have a cam system that adjusts the distance between the groups as the lens is focused. Manufacturers call this different things: Nikon calls it CRC (close range correction); Canon calls it a floating system; and Hasselblad and Mamiya call it FLE (floating lens element). Glass is the most common material used to construct lens elements, due to its good optical properties and resistance to scratching. Other materials are also used, such as quartz glass , fluorite , plastics like acrylic (Plexiglass), and even germanium and meteoritic glass . Plastics allow
4740-467: The lens designer to balance these and produce a design that is suitable for photographic use and possibly mass production. Typical rectilinear lenses can be thought of as "improved" pinhole "lenses" . As shown, a pinhole "lens" is simply a small aperture that blocks most rays of light, ideally selecting one ray to the object for each point on the image sensor. Pinhole lenses have a few severe limitations: Practical lenses can be thought of as an answer to
4819-421: The lens omit the aperture, and the shutter does double duty. The two fundamental parameters of an optical lens are the focal length and the maximum aperture . The lens' focal length determines the magnification of the image projected onto the image plane, and the aperture the light intensity of that image. For a given photographic system the focal length determines the angle of view , short focal lengths giving
SECTION 60
#17327875728014898-459: The lens's focal length divided by the effective aperture (or entrance pupil ), a dimensionless number. The lower the f-number, the higher light intensity at the focal plane. Larger apertures (smaller f-numbers) provide a much shallower depth of field than smaller apertures, other conditions being equal. Practical lens assemblies may also contain mechanisms to deal with measuring light, secondary apertures for flare reduction, and mechanisms to hold
4977-453: The light of a lamp as possible through a small sheet of glass on which was the image to be projected, and onward into a focusing lens at the front of the apparatus to project the image onto a wall or screen (Huygens apparatus actually used two additional lenses). He did not publish nor publicly demonstrate his invention as he thought it was too frivolous. The magic lantern became a very popular medium for entertainment and educational purposes in
5056-420: The light of an oil lamp or candle go through a transparent cylindrical case on which the figure is drawn to project the larger image, so it probably could not project an image as clearly defined as Fontana's drawing suggests. In 1437 Italian humanist author, artist, architect, poet, priest, linguist, philosopher and cryptographer Leon Battista Alberti is thought to have possibly projected painted pictures from
5135-533: The listed projectors were capable of projecting several types of input. For instance: video projectors were basically developed for the projection of prerecorded moving images, but are regularly used for still images in PowerPoint presentations and can easily be connected to a video camera for real-time input. The magic lantern is best known for the projection of still images, but was capable of projecting moving images from mechanical slides since its invention and
5214-633: The manufacturing of strongly aspherical lens elements which are difficult or impossible to manufacture in glass, and which simplify or improve lens manufacturing and performance. Plastics are not used for the outermost elements of all but the cheapest lenses as they scratch easily. Molded plastic lenses have been used for the cheapest disposable cameras for many years, and have acquired a bad reputation: manufacturers of quality optics tend to use euphemisms such as "optical resin". However many modern, high performance (and high priced) lenses from popular manufacturers include molded or hybrid aspherical elements, so it
5293-536: The naked eye, but minute undulations on the surface are introduced during the manufacturing process and cause the reflected rays of light to form the pattern. It is very likely that the practice of image projection via drawings or text on the surface of mirrors predates the very refined ancient art of the magic mirrors, but no evidence seems to be available. Revolving lanterns have been known in China as "trotting horse lamps" [走馬燈] since before 1000 CE. A trotting horse lamp
5372-565: The nature of what they had seen and few had ever seen other comparable media. Projections were often presented or perceived as magic or even as religious experiences, with most projectionists unwilling to share their secrets. Joseph Needham sums up some possible projection examples from China in his 1962 book series Science and Civilization in China The earliest projection of images was most likely done in primitive shadowgraphy dating back to prehistory. Shadow play usually does not involve
5451-426: The object in order to project huge clear images. See main article: Solar camera Known equally, though later, as a solar enlarger, the solar camera is a photographic application of the solar microscope and an ancestor of the darkroom enlarger , and was used, mostly by portrait photographers and as an aid to portrait artists, in the mid-to-late 19th century to make photographic enlargements from negatives using
5530-505: The papers of his friend Constantijn Huygens , father of the likely inventor of the magic lantern Christiaan Huygens . In 1612 Italian mathematician Benedetto Castelli wrote to his mentor, the Italian astronomer, physicist, engineer, philosopher and mathematician Galileo Galilei about projecting images of the sun through a telescope (invented in 1608) to study the recently discovered sunspots. Galilei wrote about Castelli's technique to
5609-431: The question: "how can a pinhole lens be modified to admit more light and give a smaller spot size?". A first step is to put a simple convex lens at the pinhole with a focal length equal to the distance to the film plane (assuming the camera will take pictures of distant objects ). This allows the pinhole to be opened up significantly (fourth image) because a thin convex lens bends light rays in proportion to their distance to
5688-405: The surface of the mirror. The book was quite influential and inspired many scholars, probably including Christiaan Huygens who would invent the magic lantern. Kircher was often credited as the inventor of the magic lantern, although in his 1671 edition of Ars Magna Lucis et Umbrae Kircher himself credited Danish mathematician Thomas Rasmussen Walgensten for the magic lantern, which Kircher saw as
5767-497: The utmoſt Pleaſure, but may be drawn with the greateſt Eaſe by any ingenious Hand." The solar microscope, was employed in experiments with photosensitive silver nitrate by Thomas Wedgwood in collaboration with Humphry Davy in making the first, but impermanent, photographic enlargements. Their discoveries, regarded as the earliest deliberate and successful form of photography, were published in June 1802 by Davy in his An Account of
5846-516: The walls, especially popular for nurseries. The inverted real image of an object reflected by a concave mirror can appear at the focal point in front of the mirror. In a construction with an object at the bottom of two opposing concave mirrors ( parabolic reflectors ) on top of each other, the top one with an opening in its center, the reflected image can appear at the opening as a very convincing 3D optical illusion. The earliest description of projection with concave mirrors has been traced back to
5925-434: The world is known as the lens's entrance pupil ; ideally, all rays of light leaving a point on the object that enter the entrance pupil will be focused to the same point on the image sensor/film (provided the object point is in the field of view). If one were inside the camera, one would see the lens acting as a projector . The virtual image of the aperture from inside the camera is the lens's exit pupil . In this simple case,
6004-501: Was common to see these night lanterns in their shop windows. A more common version had the figures, usually representing grotesque or devilish creatures, painted on a transparent strip. The strip was rotated inside a cylinder by a tin impeller above a candle. The cylinder could be made of paper or of sheet metal perforated with decorative patterns. Around 1608 Mathurin Régnier mentioned the device in his Satire XI as something used by
6083-411: Was possible to project "images artificially painted, or written letters" onto the surface of the Moon with the means of moonbeams and their "resemblances being multiplied in the air". Pythagoras would have often performed this trick. In 1589 Giambattista della Porta published about the ancient art of projecting mirror writing in his book Magia Naturalis . Dutch inventor Cornelis Drebbel , who
6162-440: Was probably at its peak of popularity when used in phantasmagoria shows to project moving images of ghosts. There probably existed quite a few other types of projectors than the examples described below, but evidence is scarce and reports are often unclear about their nature. Spectators did not always provide the details needed to differentiate between for instance a shadow play and a lantern projection . Many did not understand
6241-536: Was used for police identification work. It used a celluloid roll over a 9-inch stage allowing facial characteristics to be rolled across the stage. The United States military in 1940 was the first to use it in quantity for training. From the 1950s to the 1990s slide projectors for 35 mm photographic positive film slides were common for presentations and as a form of entertainment; family members and friends would occasionally gather to view slideshows, typically of vacation travels. Complex Multi-image shows of
#800199