International photographer (Jan-Dec 1934)

Eighteen The INTERNATIONAL PHOTOGRAPHER October, 1934 A FEW WORDS ABOUT SUNSHADES AND FILTERS SUNSHADES AND FILTERS. Such simple little devices, yet how often they are completely ignored or misunderstood by the amateur photographer ! Trust the professional cameraman, however, to appreciate and make good use of these gadgets. If you happen to be one of the clan who use these devices with success, you may go now, and skip the rest of this article, for it is aimed definitely at those workers who have so far thought their use superfluous, and for tyros (beginners, to you). Let us first consider the sunshade because it is of greatest importance — I mean to say that no exposure should ever be made without one, whereas there are times when a filter is not favorably indicated. The sunshade physically is any device which protects the lens from stray light-rays and permits only the image-forming rays to pass through the lens and thence onto the emulsion. A sunshade which is one hundred per cent efficient is an impossibility, but one which may be considered as being eighty per cent efficient is easily possible. It must be remembered that when a lens is pointed at an object, the light reflected by that object travels through the lens, thus forming the image on the emulsion. But, aside from the image-forming light, we must always contend with extraneous light such as is reflected by various other objects in the vicinity. This light, while serving no purpose for the making of the picture, finds its way to the lens and is in most cases carried to the emulsion along with the image-forming light. Needless to say, this unwanted light has its effect upon the emulsion, causing a usually faint fog, and hence dulling the picture image. With an abundance of such extraneous light, it can readily be appreciated that no little fog is present in the developed negative. The fog itself may not be readily noticeable, but it certainly does take its toll in flat, dulllooking negatives. The average developer produces a sufficiently high fog-value by itself — why increase it wantonly ? At the seashore, on sandy beaches, on the water, and in the mountains, non-image-forming light abounds in tremendous amounts, hence a sunshade is all the more important at such places. Light may be regarded as streaming in from all directions, and it is the function of a practical sunshade to prevent its entrance into the lens as much as possible, hence no exposure should be made without a generous shade over the camera lens. The sunshade likewise permits the camera lens to be more nearly pointed towards light-sources (such as the sun, for example) which usually results in better roundness and depth in the picture. Without a shade, the lens must be carefully protected, and back-lighted scenes are impossible. In short, there is no earthly reason why a shade should not be used, and a hundred why it should. I have alluded to the fact that stray light fogs the emulsion somewhat. In other words, the picture itself is dulled and lacks contrast. A picture which was made with the lens properly protected, however, has snap, brilliance, and sparkle. If you doubt this, just refer to "Factors Which Affect the Contrast of a Lens Image in the Motion Picture Camera," by Clifton Tuttle and H. E. White (Communication No. 329, Eastman Kodak Research Labs.). You will find good reason to use a sunshade on your lens, proved to you in figures and formulas. If you are still unconvinced — then better give up photography altogether. Now the problem presents itself — providing I have so far gotten you to the point of admitting that you should have a sunshade — as to what kind of a shade to get. There are two easy ways out ; either buy a manufactured shade or make one yourself. Of the former there are many makes and varieties. Usually a sunshade is made to fit a particular lens, so that if you have a number of lenses of varying outside diameter you may find yourself in difficulties in trying to get one sunshade to fit them all. However, even that is possible, for one enterprising manufacturer offers a device which can be placed in front of different lenses of various sizes. This device may be obtained from the Camera Supply Co., Ltd., 1515 N. Cahuenga Avenue, Hollywood, Calif. Another sunshade which has adjustable characteristics is the Rhaco. By means of a spring-clamp, lenses of various diameters may be accommodated. This shade is distributed by Photo Utilities, Inc., 152 West 42nd St., New York City. A third manufactured product is known as the H. C. E., and may be obtained in numerous styles and sizes to fit any lens. This one is a product of the Hollywood Camera Exchange, Ltd., 1600 N. Cahuenga Avenue, Hollywood, Calif. (Why are most of these useful accessories made in sunny California?) A fourth sunshade with universal appeal is the Woershing, handled by the Hugo Meyer Co. A fifth is the Willo, made and distributed by Willoughby's, Inc. But why go on ? There are a number of excellent sunshades available, ready made. All you have to do is to know where to go for them. And of course most lens manufacturers offer special shades for their particular lenses. A most desirable combination is one which consists of both a sunshade and a filter holder in one, and thus we find the H. C. E., Rhaco, and Willo, among others, of this type. The H. C. E. combination for the smaller sizes is a two-part proposition which unscrews. The filter is placed within the cup or receptacles made for it, and fastened in place by screwing back the other half of the unit. This idea is most practical, for it eliminates any possibility of the dropping out. In the larger sizes, the H. C. E. shade provides accommodation for the standard two-inch square filter in a metal frameholder which slides in or out of the shade proper. The Willo, too, accommodates two-inch square filters. These are merely inserted in a slot provided for them. The Rhaco outfit is designed on different principles. The shade part snaps securely into the filter-holder unit, which is a circular holder, to which the fastening springs are attached. The shade in other words holds the filter in place. This equipment accommodates round filters in the several sizes in which the shade is avai'able. Sunshades are inexpensive enough. However, if you care to make your own, you can do it easily by securing some solid, yet fairly flexible cardboard and making a Please mention The International Photographer when corresponding with advertisers.