Using mirrors it is possible to project a right-side-up image. The projection can also be diverted onto a horizontal surface e. The 18th-century overhead version in tents used mirrors inside a kind of periscope on the top of the tent. The box-type camera obscura often has an angled mirror projecting an upright image onto tracing paper placed on the glass top. Although the image is viewed from the back, it is now reversed by the mirror. There are theories that occurrences of camera obscura effects through tiny holes in tents or in screens of animal hide inspired paleolithic cave paintings.
Distortions in the shapes of animals in many paleolithic cave artworks might be inspired by distortions seen when the surface on which an image was projected was not straight or not in the right angle.
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In Arab and European cultures its invention was much later attributed to Egyptian astronomer and mathematician Ibn Yunus around CE. Some ancient sightings of gods and spirits, especially in temple worship, are thought to possibly have been conjured up by means of camera obscura projections. In these writings it is explained how the inverted image in a "collecting-point" or "treasure house" [note 1] is inverted by an intersecting point a pinhole that collected the rays of light.
Light coming from the foot of an illuminated person would partly be hidden below strike below the pinhole and partly form the top part of the image. Rays from the head would partly be hidden above strike above the pinhole and partly form the lower part of the image. This is a remarkably early correct description of the camera obscura; there are no other examples known that are dated before the 11th century.
Is it for the same reason as that when light shines through a rectangular peep-hole, it appears circular in the form of a cone? Many philosophers and scientists of the Western world would ponder this question before it became accepted that the circular and crescent-shapes described in this "problem" were actually pinhole image projections of the sun.
Although a projected image will have the shape of the aperture when the light source, aperture and projection plane are close together, the projected image will have the shape of the light source when they are further apart. Euclid is sometimes reported to have mentioned the camera obscura phenomenon as a demonstration that light travels in straight lines in his very influential Optics circa BCE. Claims could be based on later versions, since Ignazio Danti added a description of camera obscura in his annotated translation. In the 4th century, Greek scholar Theon of Alexandria observed that "candlelight passing through a pinhole will create an illuminated spot on a screen that is directly in line with the aperture and the center of the candle.
In the 6th century, the Byzantine-Greek mathematician and architect Anthemius of Tralles most famous as co-architect of the Hagia Sophia , experimented with effects related to the camera obscura. In the 9th century, Al-Kindi Alkindus demonstrated that "light from the right side of the flame will pass through the aperture and end up on the left side of the screen, while light from the left side of the flame will pass through the aperture and end up on the right side of the screen. In the 10th century Yu Chao-Lung supposedly projected images of pagoda models through a small hole onto a screen to study directions and divergence of rays of light.
Arab physicist Ibn al-Haytham known in the West by the Latinised Alhazen — explained in his Book of Optics circa that rays of light travel in straight lines and are distinguished by the body that reflected the rays and then wrote:. Moreover, if one candle is shielded, only the light opposite that candle is extinguished, but if the shielding object is lifted, the light will return.
He described a 'dark chamber' and did a number of trials of experiments with small pinholes and light passing through them. This experiment consisted of three candles in a row and seeing the effects on the wall after placing a cutout between the candles and the wall. The image of the sun shows this peculiarity only when the hole is very small. When the hole is enlarged, the picture changes, and the change increases with the added width.
When the aperture is very wide, the sickle-form image will disappear, and the light will appear round when the hole is round, square if the hole is square, and if the shape of the opening is irregular, the light on the wall will take on this shape, provided that the hole is wide and the plane on which it is thrown is parallel to it.
Al-Haytham also analyzed the rays of sunlight and concluded that they make a conic shape where they meet at the hole, forming another conic shape reverse to the first one from the hole to the opposite wall in the dark room. Ibn al-Haytham is reported to have stated about the camera obscura: In his book Dream Pool Essays the Song Dynasty Chinese scientist Shen Kuo — compared the focal point of a concave burning-mirror and the "collecting" hole of camera obscura phenomena to an oar in a rowlock to explain how the images were inverted:.
But if its image is collected shu like a belt being tightened through a small hole in a window, then the shadow moves in the direction opposite of that of the bird. Such a mirror has a concave surface, and reflects a finger to give an upright image if the object is very near, but if the finger moves farther and farther away it reaches a point where the image disappears and after that the image appears inverted. Thus the point where the image disappears is like the pinhole of the window.
So also the oar is fixed at the rowlock somewhere at its middle part, constituting, when it is moved, a sort of 'waist' and the handle of the oar is always in the position inverse to the end which is in the water. Shen Kuo also responded to a statement of Duan Chengshi in Miscellaneous Morsels from Youyang written in about that the inverted image of a Chinese pagoda tower beside a seashore, was inverted because it was reflected by the sea: It is a normal principle that the image is inverted after passing through the small hole.
English statesman and scholastic philosopher Robert Grosseteste c. English philosopher and Franciscan friar Roger Bacon c.
He is also credited with a manuscript that advised to study solar eclipses safely by observing the rays passing through some round hole and studying the spot of light they form on a surface. A picture of a three-tiered camera obscura see illustration has been attributed to Bacon,  but the source for this attribution is not given. English archbishop and scholar John Peckham circa — wrote about the camera obscura in his Tractatus de Perspectiva circa and Perspectiva communis circa , falsely arguing that light gradually forms the circular shape after passing through the aperture. At the end of the 13th century, Arnaldus de Villa Nova is credited with using a camera obscura to project live performances for entertainment.
French astronomer Guillaume de Saint-Cloud suggested in his work Almanach Planetarum that the eccentricity of the sun could be determined with the camera obscura from the inverse proportion between the distances and the apparent solar diameters at apogee and perigee. He determined the eccentricity of the sun based on his observations of the summer and winter solstices in Levi also noted how the size of the aperture determined the size of the projected image. Italian polymath Leonardo da Vinci — , familiar with the work of Alhazen in Latin translation [ citation needed ] and after an extensive study of optics and human vision, wrote the oldest known clear description of the camera obscura in mirror writing in a notebook in , later published in the collection Codex Atlanticus translated from Latin:.
If the facade of a building, or a place, or a landscape is illuminated by the sun and a small hole is drilled in the wall of a room in a building facing this, which is not directly lighted by the sun, then all objects illuminated by the sun will send their images through this aperture and will appear, upside down, on the wall facing the hole. You will catch these pictures on a piece of white paper, which placed vertically in the room not far from that opening, and you will see all the above-mentioned objects on this paper in their natural shapes or colors, but they will appear smaller and upside down, on account of crossing of the rays at that aperture.
If these pictures originate from a place which is illuminated by the sun, they will appear colored on the paper exactly as they are. The paper should be very thin and must be viewed from the back. These descriptions, however, would remain unknown until Venturi deciphered and published them in Da Vinci was clearly very interested in the camera obscura: He systematically experimented with various shapes and sizes of apertures and with multiple apertures 1, 2, 3, 4, 8, 16, 24, 28 and He compared the working of the eye to that of the camera obscura and seemed especially interested in its capability of demonstrating basic principles of optics: Italian polymath Gerolamo Cardano described using a glass disc - probably a biconvex lens - in a camera obscura in his book De subtilitate, vol.
He suggested to use it to view "what takes place in the street when the sun shines" and advised to use a very white sheet of paper as a projection screen so the colours wouldn't be dull. Sicilian mathematician and astronomer Francesco Maurolico answered Aristotle's problem how sunlight that shines through rectangular holes can form round spots of light or crescent-shaped spots during an eclipse in his treatise Photismi de lumine et umbra However this wasn't published before ,  after Johannes Kepler had published similar findings of his own.
Italian polymath Giambattista della Porta described the camera obscura, which he called "obscurum cubiculum", in the first edition of his book series Magia Naturalis. He suggested to use a convex mirror to project the image onto paper and to use this as a drawing aid. Della Porta compared the human eye to the camera obscura: The popularity of Della Porta's books helped spread knowledge of the camera obscura. In his work La Pratica della Perspettiva Venetian nobleman Daniele Barbaro described using a camera obscura with a biconvex lens as a drawing aid and points out that the picture is more vivid if the lens is covered as much as to leave a circumference in the middle.
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In his influential and meticulously annotated Latin edition of the works of Al-Haytam and Witelo Opticae thesauru German mathematician Friedrich Risner proposed a portable camera obscura drawing aid; a lightweight wooden hut with lenses in each of its four walls that would project images of the surroundings on a paper cube in the middle. The construction could be carried on two wooden poles. Around Italian Dominican priest, mathematician, astronomer, and cosmographer Ignazio Danti designed a camera obscura gnomom and a meridian line for the Basilica of Santa Maria Novella , Florence and he later had a massive gnomon built in the San Petronio Basilica in Bologna.
The gnomon was used to study the movements of the sun during the year and helped in determining the new Gregorian calendar for which Danti took place in the commission appointed by Pope Gregorius XIII and instituted in In his book Diversarum Speculationum Mathematicarum  Venetian mathematician Giambattista Benedetti proposed to use a mirror in a 45 degree angle to project the image upright. This leaves the image reversed, but would become common practice in later camera obscura boxes.
He also described use of the camera obscura to project hunting scenes, banquets, battles, plays or anything desired on white sheets. Trees, forests, rivers, mountains "that are really so, or made by Art, of Wood, or some other matter" could be arranged on a plain in the sunshine on the other side of the camera obscura wall.
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Little children and animals for instance handmade deer, wild boars, rhinos, elephants and lions could perform in this set. The Hunter he must come with his hunting Pole, Nets, Arrows, and other necessaries, that may represent hunting: Let there be Horns, Cornets, Trumpets sounded: Swords drawn will glister in at the hole, that they will make people almost afraid.
They admired it very much and could hardly be convinced by Della Porta's explanations that what they had seen was really an optical trick. The earliest use of the term "camera obscura" is found in the book Ad Vitellionem Paralipomena by German mathematician, astronomer, and astrologer Johannes Kepler.
He also realized that images are "painted" inverted and reversed on the retina of the eye and figured that this is somehow corrected by the brain. It is believed he later used a telescope with three lenses to revert the image in the camera obscura. In 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 to study the recently discovered sunspots.
Galilei wrote about Castelli's technique to the German Jesuit priest, physicist and astronomer Christoph Scheiner. From to at least Christoph Scheiner would keep on studying sunspots and constructing new telescopic solar projection systems. He called these "Heliotropii Telioscopici", later contracted to helioscope. Scheiner also made a portable camera obscura. The image of an assistant with a devil's mask was projected through a lens into the dark room, scaring the uneducated spectators.
By Kepler used a portable camera obscura tent with a modified telescope to draw landscapes. It could be turned around to capture the surroundings in parts. Dutch inventor Cornelis Drebbel is thought to have constructed a box-type camera obscura which corrected the inversion of the projected image. In he sold one to the Dutch poet, composer and diplomat Constantijn Huygens who used it to paint and recommended it to his artist friends. I have at home Drebbel's other instrument, which certainly makes admirable effects in painting from reflection in a dark room; it is not possible for me to reveal the beauty to you in words; all painting is dead by comparison, for here is life itself or something more elevated if one could articulate it.
The figure and the contour and the movements come together naturally therein and in a grandly pleasing fashion. German Orientalist , mathematician, inventor, poet, and librarian Daniel Schwenter wrote in his book Deliciae Physico-Mathematicae about an instrument that a man from Pappenheim had shown him, which enabled movement of a lens to project more from a scene through the camera obscura.
It consisted of a ball as big as a fist, through which a hole AB was made with a lens attached on one side B. This ball was placed inside two halves of part of a hollow ball that were then glued together CD , in which it could be turned around. This device was attached to a wall of the camera obscura EF.
Italian Jesuit philosopher, mathematician and astronomer Mario Bettini wrote about making a camera obscura with twelve holes in his Apiaria universae philosophiae mathematicae When a foot soldier would stand in front of the camera, a twelve person army of soldiers making the same movements would be projected. He explained how the camera obscura could be used by painters to achieve perfect perspective in their work. He also complained how charlatans abused the camera obscura to fool witless spectators and make them believe that the projections were magic or occult science.
These writings were published in a posthumous version of La Perspective Curieuse The use of the camera obscura to project special shows to entertain an audience seems to have remained very rare. A description of what was most likely such a show in in France, was penned by the poet Jean Loret. The Parisian society were presented with upside-down images of palaces, ballet dancing and battling with swords. The performance was silent and Loret was surprised that all the movements made no sound. Loret felt somewhat frustrated that he did not know the secret that made this spectacle possible.
She pinned the material together. The fallen tree pinned him to the ground. A pinhole camera does not need a lens. He pinpointed the position on the map.
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He has dozens of pin-ups in his room; also adjective a pin-up girl. She's the favourite pin-up of the soldiers. I can't pin him down to a definite date for his arrival. I've got pins and needles in my arm. References in classic literature? Again and again I went carefully over every square inch of its surface, but the most that I could find was a tiny pinhole a little above and to the right of the door's center--a pinhole that seemed only an accident of manufacture or an imperfection of material.
I thought I knew, and, seizing a powerful magnifying glass from the litter of my pocket-pouch, I applied myself to a careful examination of the marble immediately about the pinhole in the door.
It was evident that for countless ages radium torches had been applied to this pinhole , and for what purpose there could be but a single answer--the mechanism of the lock was actuated by light rays; and I, John Carter, Prince of Helium, held the combination in my hand--scratched by the hand of my enemy upon his own torch case. For fifty tals I let three units of light shine full in the pinhole , then one unit for one xat, and for twenty-five tals nine units.
Little Toomai turned, rustling in the fodder, and watched the curve of his big back against half the stars in heaven, and while he watched he heard, so far away that it sounded no more than a pinhole of noise pricked through the stillness, the "hoot-toot" of a wild elephant.