All technical inventions with regard to moving pictures are based on the same optical principle nature makes use of for millions of years: the human eye sees something in the same way the “eye” of the Camera Obscura does.
The term comes from the Latin language and means “dark room”.
The basic principle of the Camera Obscura is very simple, because every object, whether bright or reflecting, is sending rays of light in all directions, which are spread in a straight line. When these rays of light enter a dark room through a little hole, they are combined to one beam of light because of the diameter of the hole and project a picture on the opposite wall. It is a mirror-converted reproduction.
The observation of light in the dark room was already known as an optical phenomenon by the philosopher Aristotle in the fourth century before Christ.
The technology in the Broich watertower
The lens system consists on the one hand of a swivelling mirror that can be tilt and, on the other hand, of an objective that is able to focus the environment.
The mirror has a free diameter of 300 mm.
The objective is a system with three lenses which has a hole of 140 mm and an opening with a
proportion of 1:65.
The distance between the objective and the projection surface is approximately 9 m.
- Both the angle of the object and the angle of the picture is 8°.
The Camera Obscura in Mülheim enables
A complete panorama view from the “MüGa” parklands to the horizon,
A sharp reproduction of objects at a distance of 13 m to infinity by means of the focus of the lenses.
- A diameter of the picture on the projection surface of 1400 mm.
With this technology the Camera Obscura permits a natural observation of the environment within the complete dark room in the former water tower. There is the projection surface where approximately 25 visitors can get enthusiastic about the phenomenon of the “pinhole camera”.