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The Optical Magic Lantern Journal and Photographic Enlarger. 95
In the engraving Fig. I. is illustrated quite a novel camera, the invention of G, Francis Jenkins, for making accurately the continuous series of pictures. Instead of using a rotary dise shutter with radial apertures and a fixed lens, this camera has a single opening in the front, the size of the aperture being regulated at its rear end by a diaphragm disc having radial slots cut therein of varying widths. The opera
tor is thereby enabled to govern the amount of light admitted to the lenses according to the subject to be photographed and the length of exposure desired. This disc is rotated by hand on its axis like an ordinary stop in a wide angle lens.
Back of the diaphragm disc is observed the battery of lenses, each of the same focus,
Fig. I.
arranged in a circle, adjoining each other upon a rotating disc, the axis of which extends rearward, terminating in a bevel gear wheel, which meshes into a side bevel gear wheel, fixed upon the upper shaft, suitably geared to the main driving shaft. The main shaft may be operated by a crank on the outside of the box, by hand or by any suitable motor like a spring. The sensitised celluloid perforated ribbon film will be noticed passing downward near the front end of the camera in front of the exposure tension plate, the square aperture in which is exactly in line with the front aperture in the box. From this point the film, after exposure, passes downward between the sprocket wheel and pressure roller to the winding reel in the rear end of the camera, which is rotated by belt connection to a pulley on the upper shaft, and takes up the film ribbon as rapidly as it is exposed. The feed roll for the supply of fresh film is not shown, but may be located in the rear of the camera over the winding reel,
The operation may now be readily understood; to obtain successive pictures of a particular object, the camera is placed on a stand or tripod, the crank on the outside is then rotated, which causes the film to travel downward continuously, with exactly the same speed that the lenses rotate, so that at every fraction of a second that it takes for each lens to pass behind the camera aperture, an impression of light is made on the downwardly moving film, and as they (the lenses and film) both move in
Fig. IT,
unison, it follows that a sharp picture must be the result, while the brilliancy of the illumination is at its maximum. The camera can be carried about as readily as any other camera, and in practice it is found the motion of the hand-operated crank is sufficiently uniform to permit of the proper reproduction of motion by the positive pictures when projected on the screen.
Fig, III.
The Figures II. and III. show the method of printing the positive ribbon pictures from the negative by means of artificial light, also designed by Mr. Jenkins. It consists of reels supported on suitable upright standards holding respectively the sensitive ribbon film and the