High-speed Camera

Abstract

K. M. BAIBD (Can. J. Res., 24, 41 ; 1946) has described, in outline, an ultra high-speed motion-picture camera, embodying new principles, which, it is expected, will enable pictures of good resolving power and illumination to be taken at rates as high as 200,000 per second. A set of lenses, mounted in a row, forms a set of images which are projected by a lens system on to rotating reflecting prisms, one prism for each lens in the row, and thence to the film which is wound in a single layer on a drum. A rotating sector placed in front of the set of lenses acts as a shutter. The sector has equidistant radial slots, so spaced that after a given slot has just passed the last lens in the row, the next slot comes opposite the first lens. Thus, the camera takes several pictures while the film moves the distance of only one, with corresponding advantage over the conventional type of camera. Intense illumination is required but this need be of only very short duration, since any event requiring a high-speed camera naturally lasts only a very short time. To test the practicability of the design of the proposed camera, an experimental model was constructed, in which the lens system and rotating prisms were not included. In spite of these omissions, quite good pictures were obtained at rates of 70,000 a second, and a series of pictures, taken at the rate of 64,000 per second, of a rifle bullet fired at and piercing an electric light bulb, is included in the paper, illustrating very clearly the capabilities of the camera.