What is a camera obscura and as it works?
there was to me in the childhood a strange occurence: I stand at an entrance and suddenly I notice unclear drawing on a wall. Having looked narrowly at it, I understood that it no other than the image of the house on the contrary seen through a keyhole at entrance doors. But that is interesting, this image was turned head over heels!
What then could not understand in any way is how the house could be reflected and appear on a wall. I remembered this mysterious history, and many years later me coincidence helped with it to understand. One my acquaintance, having read V. V. Nabokov`s novel “ Camera obscura “ asked to learn what is it. Here - that I also decided to understand this phenomenon finally.
Obscura - dark is translated from Latin of camera as the room, and. Dark room. By definition it turns out that the camera obscura is a prototype of the camera, this dark room with one tiny opening through which on an opposite wall the turned reduced image of objects outside is projected.
When the camera obscura was invented, it is definitely not known, but in the 5th century BC the Chinese philosopher Mi Ti described emergence of the image on a wall of the darkened room. Mentioned such chamber also Aristotle. Photo history when through a small opening on paper projected the image of a subject also began with it - that.
The chamber and to many artists helped, so Jan Vermer with its help reached in city landscapes of almost photographic objectivity. And it was in the 17th century, long before the invention of the camera. Possibly, the first used the camera to sketches of landscapes of Leonardo da Vinci. Widely among artists the camera obscura began to be used in the 18th century. And before, in the Middle Ages, feudal lords built in the locks dark rooms with the openings which were going outside to see what occurs behind walls, without getting up from a bed. However, head over heels...
Our eyes also work by the principle of the camera obscura strengthened by optical system in the form of a crystalline lens and an eyeball capable to reproduce accurate images irrespective of range of object. But not all systems of the image have lenses. So a marine animal Nautilus has an eye in the form of a tiny opening, sharpness of the image increases by reduction of its diameter.
The camera obscura allows to observe solar spots. And that is interesting, in the Middle Ages Gothic cathedrals in which it was almost daily possible to observe a sun surface were constructed. And on May 18, 1607 Kepler took by mistake the image of a small dark speck on a solar disk in a camera obscura for Mercury.
Presently the camera obscuras mounted in many cities of the world are used for science and education, and also for the sake of an entertainment. The pictures taken by means of a camera obscura differ in softness of drawing, semi-blurring and lack of some types of the distortions peculiar to more difficult optical devices, but sharpness of the image at them is low. Near objects turn out more indistinct, than remote. For increase in brightness and sharpness of the image the lens is used.
We will put experience. Let`s take a matchbox, we will make in the middle a small opening in half-millimeter diameter, we will place at the bottom a box photographic paper or a film for the camera (without having lit at the same time) and, having directed to a lens to the street, we will leave for about four hours. Let`s open and will look what turned out.
Beams fall on object of shooting, are reflected from it, pass through an opening in a camera obscura and are fixed on photographic paper. The opening is less, the less foreign beams from each point of object will be able to pass and be displayed through it on photographic paper. Therefore, those more accurate will turn out a picture of the represented object. And if the opening big, a photoprint does not turn out - paper will just be lit.
With a little complicated and increased chamber - to boxes, photographic prints will turn out more accurate and the bigger size. And it is possible to complicate it so: take a box of the big sizes, in the center of a wall where the opening will settle down, cut out a rectangle about 2 × 3 cm, attach an adhesive tape on its place a foil, previously having done in it an accurate dot opening. In a box, on the party, opposite to an opening, arrange a film. It is even simpler to take the old camera, to screw together from it a lens, to stick a hole with black paper or a foil and to do in it a small opening. Only do not forget to clean a lock blind that light could get on a film.
I wish success in experiences and, as a result, interesting photos.