Motography (Apr-Dec 1911)

^^— — ^— 194 MOTOGRAPHY Vol. VI, No. 4. house. The accompanying illustration shows a front the company designed for the Victoria Theater, Chicago, recently, and is an example of a beautiful effect attained * for a very low cost. Any theater man interested in improving the looks of his house can have the company representative get up pencil sketches and quote prices on application. American Made Projection Lenses It was not many years ago that the American, who wished to do any careful work in optics, thought he must look to the Old World for his lenses. The German, Frenchman and even our English cousin had been doing that sort of thing for generations. They possessed the formulae, the skilled workmen to execute the formulae and the prestige behind their products. An American lens was regarded with suspicion by the exacting. This was tor years the case with projection lenses. Even after American manufacturers had begun to make projection apparatus they thought it necessary to import all the lenses with which to equip their lanterns. They had no facilities, in fact, for doing otherwise. When the Bausch & Lomb Optical Company, at Rochester, N. Y., turned its thought to optical projection, however, the projection lens was the first thing to command its attention and the first thing it produced in that line. It was a lens grinding industry primarily, possessing the scientists, the skilled workmen and the experience. It had been grinding eyeglass lenses of a high grade since 1853 and had been producing highly corrected lenses for microscope objectives and condensers since the early 70's. It was beginning the manufacture of photographic lenses, and the projection lens, involving practically the same elements as the photographic, naturally did not present a difficult proposition. This company, then, disregarded precedent and began the manufacture of lenses for projection long before it began making its well known Balopticons or lanterns, in which field it has since become recognized as a leader. It sold those lenses to the users of projection lanterns as rapidly as it could educate them to the fact that better objectives could be made on this side of the water than they could import from Europe. Today the Bausch & Lomb Optical Company is among the greatest manufacturers of projection lenses in the world, on either side of the water. It not only grinds all the lenses, both projection and condensers, which it uses on its big output of scientifically constructed lanterns, but supplies the lenses with which the moving picture machines in a great number of the picture theaters of America are equipped. Several years ago this great American company effected a corporate alliance with the Carl Zeiss Optical Works, of Jena, Germany. As the members of the latter company and their scientists had long been recognized as the leaders of Europe in scientific optical research and production, the importance to the optical world of a union between these two companies is obvious. It has meant united effort, with an interchange between the two of ideas, experiments, and, to a certain extent, facilities. The result has been of inestimable advantage, not alone to the two companies, but to the users of optical instruments and products everywhere. It enables the Bausch & Lomb Optical Company to improve still further its lines of projection lenses, adding to it photogra phic anastigmat lenses of the highest type, constructed upon the Zeiss formulas. The quality of glass used is a big factor in the production of high grade lenses, and in this connection the alliance with Zeiss plays an important part. It has meant the establishing of intimate relations with the collaborators of that company, including particularly Schott & Genossen, manufacturers of the best optical glass. Thus has the Bausch & Lomb Optical Company transplanted to America the optical genius, scientific and productive, so long supposed to thrive in the European climate alone. The American users of projection lenses today can find a double satisfaction in the convenience of purchasing their lenses at home and in the pleasurable knowledge that their countrymen can make as good lenses as the human mind can devise and human facilities produce. Gundlach Projection Lenses A chance remark brought about the interest of the GundlachManhattan Optical Company in projection lenses. The company found, upon investigation, that few high-grade lenses were on the market at that time — about two years ago. How could there be at the price ordinary lenses cost? Poor lenses are deficient in several ways. They are not properly corrected for optical errors, carelessly made and inaccurately mounted, produced from ordinary glass not fit for lenses and they are also incapable of giving good illumination. With little competition it looked as if the company might do good business with finer lenses — lenses so good that any exhibitor would buy one after seeing how much better it made his picture. The first lenses were finally ready and fried in Rochester, with gratifying results. They improved every picture, and the rest was easy, as exhibitors are enterprising and know that better pictures mean more receipts at the box office. If you take a piece of steel about as thick as paper and as wide as the film, drill it full of holes the size of a needle and put it in the machine in place of the film you will find that ordinary lenses give a double image of the holes on the screen, rainbow colors, and the steel or opaque portion which should be black on the screen is grey, all the holes are not equally sharp and perhaps none, as the whole effect may be hazy. Now put a good lens, such as the Gundlach, to the same test and note the difference. The double images disappear, the holes are brilliantly white and the opaque parts are perfectly black, as they should be. The definition is uniformly fine and each hole is clear cut and brilliant. This result can only be obtained by makinglenses with the greatest care from suitable optical glass and mounting them with precision. The great illuminating power of Gundlach lenses is due to their larger diameter in proportion to the focal length. Now we come to an important matter — the focal length. A picture of a certain size at a given distance can only be made with a lens of proper focus ; for example, a 12 by 16 foot picture at 72 inches requires a lens of 4.23 inches focus, or 2/100 less than A]/\ inches. The company considered it necessary to figure the focal lengths clown as fine as this, and fills each order with lenses with 5/100 of the focus required so the picture is always within an inch or two of the size specified. There is no guess work about this. If the measurement from the lens to the center of the screen is correctly stated the