IN THIS ISSUE A Road for Rays of Light Page 1 The lens designer at work They Scored High in Quiz Page 2 A knowledgeable foursome Beaver Skins and Pieces of Eight Page 3 For a fancy shirt, two hides Panorama P age 4 Pantoscopic patter They Have Retired from Kodak Service P age 5 Saluting former colleagues It's a Gigantic Housekeeping Job Page 6 Keeping the city livable Another Kodak Year Is Reviewed P age 7 Background of the balance sheet Kodak's Balance Sheet for 1940 P age 8 What we own, what we owe The Editor's Page Page 10 "The good earth" A Common Fund for Community Needs Page 11 The Chest system is described 1940 in the World of Photography P age 12 Highlights from an annual review Activities In and Around the Plants Page 14 Sports notes up to press time Activities Calendar Page 14 Here's what's ahead Out of the Hat Page 15 Soprano; restorer Interplant Bowling Winners P age 16 They earned Lovejoy Trophy "Vantage Point" Inside Back Cover In our photograph gallery EKTAR LENS Copyri ght, 1941, by the E astman Kodak Company Volume 20 APRIL 1941 Number 4 A Road for Rays of Light The Lens Designer Must Plot A Veritable Highway Through Many Types of Optical Glass IT DOESN'T TAKE a trained civil en- gineer to understand some of the problems which must inevitably arise in laying out a new road to run, let us say, between one city and another. We can foresee that such a road will not run in a straight line, though such would hypothetically be the best route, and we can surmise that the surveyors for that road will take advantage of natural topographic features wherever they can and they will overcome all topographic ob- stacles as best they can. Eventually, they will have mapped out the most feasible route for their road, though it may appear a rather poor com- promise to carping sticklers for per- fection. Roads through Glass Now, there is another kind of road- way which offers somewhat compa- The life story of a Kodak lens begins with a vast number of figures. Even with the aid of a modern rable problems in being laid out, and computing machine and mathematical tables, it often requires many months to compute a new lens formula this is the route that lens designers just the sort of disturbance that must give a great deal of attention plot through pieces of optical glass to bends them from their normal course. to such considerations as attractive carry rays of light into a camera. But this bending is essential in that appearance, a high degree of com- Here again, there is a hypothetically it serves to focus points of light on pactness, a popular film size, a rea. on- correct route which would lead those one focal plane. In the process, un- able retail price, and so on . But the rays to produce a perfect image at fortunately, it raises some tremen- incorporation of these very necessary their destination-the focal plane of dous problems which the lens designer features may add considerably to the the camera- but certain obstacles must seek to overcome. lens designer's problems, for he is along the way make this goal very We ought to look at these problems held within very strict limits. H e difficult to attain so that the lens for a moment and see just why it is must design his lens to fit the specific designer, like the road surveyor, must so difficult to guide rays of light into needs of a camera, since those sales be satisfied to reach the most feasible a camera in a satisfactory way. considerations hardly permit the de- solution and leave perfection to the signing of a camera to fit a lens. So, angels! Sales Angles when the time comes, after the final Now, one of the strange things When a new camera is designed at design of a camera with sales-appeal about the lens designer's job is the Camera Works, the ruling considera- has been decided upon, the Camera fact that rays of light always travel tion is that it should appeal, in its Works engineers turn to the Scientific in a straight line unless disturbed, final form, to Eastman customers and Department at Hawk-Eye and say and yet he lays out a road for them thus lead them to desire it and to buy in about so many words, "Here's a through optical glass which introduces it. So the Development Department new camera we have just designed Page 2 K 0 D A K suffer from defects which are known They Scored High 1n Quiz as aberrations. In order to reduce these, the lens designer uses different kinds of glass to balance the errors of one lens element against those of another having different optical prop- erties. - Final Steps In the meantime, the designer must keep in mind the final require- ments for his lens, and it may be that these requirements will force him to introduce as many as seven or eight elements into his lens. If they do, he is soon swimming in a turbulent sea of figures- thousands and thousands of them. He no more than overcomes one mountainous obstacle when he runs smack into another which may even force him to retrace his steps and start all over again in a new direction. Eventually, all errors are satisfactorily balanced out, and such requirements as focal length and Facing the mike and th e genial quizzer is the no-less-genial Kodak Office foursome that knew all speed are satisfactorily fulfilled. Tools the answers-well, enough of 'em to come out " tops" - in a recent intercity quiz contest. Reading from left: William A. Vaughn, Patricia leek, Jeremiah G. Hick ey, Jr. , and Doris Weber are then prepared for grinding the lens, a sample lens is made and tested, and production begins. for Mr. Consumer. We're satisfied they were good. If his lens didn't that it will appeal to the buying serve properly as a pathway for rays Kodak's Contributions public, and now we need a lens for it. of light, he had to try again and again The Eastman Kodak Company has Below you'll find the specifications until he attained a reasonably satis- contributed greatly to progress in lens which this lens should meet in the factory result. Lens designing was design. Most of us are familiar with way of focal length, coverage, speed, just a matter of hit and miss in those how the Company has brought about and cost limitations. Please see what days, and even the best hits weren't a lowering of the price of fine lenses you can do for us." bull's-eyes by a long way. by its advanced methods of manu- Today, lens designing is done facture, but few of us know how much Problems Pop Up mathematically, largely with the help our own scientists have contributed Now, this is a much larger order of automatic calculating machines. to improved methods of computing than you might ever suspect. It in- And because the lens designer is lenses. A staff of more than twenty volves the mathematical computation familiar with the optical properties of members in the Scientific Depart- of an entirely new lens- and if you his glass and its effect upon rays of ment at Hawk-Eye devotes its entire think that is a simple job you should light, he knows that a satisfactory time to computing new lens formulas, see the volumes of figures represent- solution to his problem on paper will and the records of that department ing months and even years of labor lead to proper performance of his lens contain a treasure of recorded experi- that have gone into other Kodak in actual practice. The problem is, ence gained in the past to guide its lenses. It isn't, we repeat, a simple of course, to reach that satisfactory efforts in the future. New contribu- job, because to survey and lay out a solution on paper- and that is gen- tions are made each day to this store- road for waves of light requires that erally an arduous and drawn-out house of scientific findings. the lens designer overcome a great business. But the lens designer, in his more many obstacles, some rather moun- communicative moments, will tell Action on Light tainous in their way of obstructing you that row upon row of mathe- the progress of his work. The chief trouble is, as you prob- matical figures is not by itself enough A hundred years ago, when photog- ably know already, that glass not to assure the successful computation raphy was an infant and the science only refracts or bends light- a very of a new lens formula. Years of experi- of optics still crept uncertainly about necessary property for bringing the ence are needed to give him a "feel" in its swaddling clothes, the lens rays to a focus-but it also disperses designer had very incomplete knowl- the light into all the colors of the - a kind of directional sixth sense- edge and inadequate theories to rainbow. It might be thought that a which aids him in plotting pathways guide him. He had to grind his lenses, lens could be made out of a single through optical glass over which light fit them in a mount, and then find by piece of glass. So it could, but it waves may pass on their way to practical application whether or not would not be a good lens, for it would forming a sharp photographic image.