Kinematograph year book (1944)

British Production. 275 James A. Sinclair & Co., Ltd. — At the present time all the manufacturing facilities of the NewmanSinclair factory are devoted to the production of the Model E. Auto-Kine Camera — that is, the latest type with lenses in panel mounting, and so designed to carry any lens from 1 in. focal length upwards. This model has the automatic release of the film lock at the beginning of a shot, and the film hold at the termination. Some variations of the basic design are made for the specialised requirements of differing Services. We anticipate in the post-war period a continuance of manufacture of the Model E. cameras, and a resumption of production of the Model D., with turret head holding four lenses. W. Vinten, Ltd.— During the past year the firm has been engaged on Government work to almost full capacity. The demand for the H.S. 300 high-speed camera for research and experimental purposes has shown its exceptional value. The performance of this camera has aroused keen interest in industrial and other circles, this being reflected in the many inquiries from commercial quarters which have been received. Special types of equipment have been evolved for purposes relating to the war, and when it is possible to make these available to the trade they will be most beneficial in improving technique and efficiency. Amongst the equipment may be mentioned new cameras of several types, which will stand most favourable comparison with existing cameras of their class. From the numerous inquiries, ranging from cameras to laboratory necessities, received from overseas sources — -both foieign and the Empire — a degree of optimism may be justifiably claimed for export trade, when normal facilities for manufacture are restored. Bell & Howell. — 'The standard Bell & Howell studio camera has proved its quality and durability under difficult conditions during the year. There have been no new developments of the essential design, although most are now equipped with the new focusing device— quick action shift from usual focusing. The accuracy of registration contributes to its popularity, and the inherent principle of the mechanism makes the camera of great utility for background work in optical projection. Lens. — -Important developments in camera lenses are hinted at by Taylor, Taylor & Hobson, Ltd., particularly as regards highly corrected, largeapertured lenses for use in radiography. Another important advance is in the surface treatment or " blooming " of interior surfaces of lenses. This latter process, one of evaporation of a surface film of lithium, magnesium or calcium fluoride on to the air glass surface of each component lens, suppresses surface reflections, so that such treated glasses pass more light than untreated ones. ' ' The research and technique employed in these and other advances will be reflected in the post-war products of this well-known firm for the kinematograph industry." The subject of coated lenses was discussed at the B.K.S. by K. M. Greenland, Ph.D., A.Inst.P. He pointed out that the lightness of the image was seriously reduced by the reflection of light at the surfaces of each glass which may vary from 4 per cent, to 7.5 per cent. This had been obviated in the coated lens by reflecting the light so that the reflected components are mutually destructive. This is achieved by putting on the lens a thin film so that the rays reflected at the air-film boundary and those reflected at the filmglass boundary are equal in intensity but of opposite phase. This is ensured by correct adjustment of the thickness and refractive index of the film. The light energy which is no longer reflected is by no means lost ; it is restored to the transmitted beam, with the happy result that the brightness of the image is increased. Several materials can be used for the film, the simplest being silica, which has the advantage of being part of the glass structure, and by a high-vacuum process, invented by Dennis Taylor, of Cooke Lenses, such a film can be commercially produced. Soviet technicians have designed and produced a special long-focus lens which has a range of 10 kilometres. Details are lacking.