Photopgrahic Outfit And Manipulations
( Originally Published 1902 )
As the outfit necessary for the thoroughly equipped nature photographer is of great importance, the reader must pardon what may appear to him to be an unnecessary amount of detail, and also excuse any statements that conflict with his ideas. Each man sees things in a different way, and I simply give my opinions, which, though based on a fair amount of experience, are not supposed to be final. To influence a man in the choice of cameras or developers or plates would be almost, if not quite, as absurd as trying to tell a man which gun to use. It is not for the advanced student in nature photography that this chapter is written, but for the tyro, who, in beginning the work of photographing things natural, runs up against a list of apparatus as long as it is perplexing. If he goes to a dealer he will more than likely be recommended to use the things upon which the dealer makes the greatest profit; he also will be induced to buy a number of quite unnecessary things; and as the dealer is seldom a really practical photographer, many of the most important articles will be left out. A great difficulty in giving anything like a complete list of apparatus needed is the constant change in all photographic supplies. A camera that would be best today might in a week's time be superseded by something so much better that the older one would be thrown aside for the newer invention. It is not so very long ago that the twin-lens camera, commonly called the two-decker," was the only camera with which one could focus on an object and at the same time have the plate ready for an exposure. Then came the reflex, and now we have the graflex, which, though expensive, is about all that can be wished for. Being strongly made, it will withstand the rough usage incidental to natural-history photography. Its long draw of bellows allows of the use of a twelve-inch lens, and for objects up to within about ten feet distant a six-inch lens with hand-camera telephoto attachment can be used. The shutter is of the latest pattern of focal plane which works near the plate; by this method the greatest possible amount of illumination is received by the plate, so that very short exposures may be given with good results. All these advantages, combined with the ease of focussing on any object, whether at rest or in motion, make such a camera of the greatest possible value to the photographer of animate nature. A bird may be caught on the wing with as much ease and certainty as if it were mounted.
For flowers and many kinds of work the regular long-focus camera will always be useful, but it is well to remember that there is every advantage in having the back focus rather than the front. The reason is obvious. The back focus allows you to keep a certain distance between the lens and the object while you move the back end of the camera until the correct focus is obtained, whereas, if the back is rigid and the front moves, you have much trouble in getting a sharp focus on a very near object, as the distance between the object and the lens changes while you are trying to get the correct focus. Almost all the modern cameras are fitted with convenient reversible backs, and most necessary arrangements they are. It is hard to realise that but a few years ago the whole camera had to be reversed, where now only the back need be moved. The swing-back is another desirable feature in a camera, far more so than the rising front, which is seldom wanted, except where buildings are to be portrayed. The use of the swing-back is not always understood by the beginner : its object is to enable him to bring both foreground and distance in focus. This is particularly noticeable when the subject in hand is a birds nest or some such object on the ground, and you have to place the camera low down. The part of the foreground nearest the lens is so very near, while the distance is so much farther off, that, to have the whole picture in even fairly sharp focus, you would have to use the smallest diaphragm, and consequently a very long exposure would be needed. By using the swing-back, swinging the upper part back and the lower part forward, you can to a limited extent obviate this. Remember that the nearer the object is to the lens the greater must be the distance between the lens and the plate, and vice versa; and as the back swings, so does it increase or decrease the distance between the lens and the plate.
In the matter of lenses there are several important things for the nature photographer to bear in mind. Speed is absolutely necessary in most branches of work; depth of focus also is necessary ; perfect definition and covering power are equally important. To insure covering power it is advisable to have a lens whose covering capacity is at least one inch greater than the largest plate you intend to use. Then if you use the rising and falling front you can use it without sacrificing definition at the upper or lower end of the plate. Length of focus is important, in that it governs the size of the object from a given distance. The greater the equivalent length of focus the larger will be the object, and the less will be the distortion due to foreshortening. A short-focus lens fore-shortens all objects that are near with such abruptness as to cause grotesque distortion. The most useful lens for all-round work is one whose two systems or combinations can be used separately. By having such a lens you have practically two in one, the single combination having about double the focal length- of the couplet. With some of the newer lenses, such as the plastigmat, the single combinations may be used for instantaneous work, while with some of the other highest grade lenses the single combinations can be used only with a small diaphragm. The diaphragm of a lens is used — to give a very untechnical description—to increase the depth of focus and the covering capacity of a lens, thereby giving greater definition at the sacrifice of speed. Each number, such as F 8, F 16, etc., means, for practical use, that the exposure when the larger figure is used shall be double that of the preceding figure ; for instance, if, with the diaphragm set at F 16, the exposure needed is one second, at F 32 it would require two seconds, and at F 64 four seconds. It will be seen by this that for instantaneous work the lens must be used either open or with a large diaphragm.
On the subject of telephoto lenses we must confine ourselves to their practical use. The telephoto is an attachment which is used in connection with another lens. It is placed back of the lens and enlarges according to the scale marked on the barrel. As the magnification increases, so is the necessary exposure lengthened, for which reason it will be seen that for instantaneous work a magnification of, say, i o diameters would be out of the question. With the Bausch & Lomb hand-camera telephoto attachment fitted to the plastigmat lens, exposures of one hundredth part of a second may be made if conditions are very favorable and the magnification is not more than about 2 1/2 or 3 diameters. Of course such a plate must be developed carefully. With an expo-sure of a twenty-fifth of a second, excellent results can be obtained in bright light. The high-power telephoto' lens is only useful when the object to be photographed is still enough to allow of a time exposure. When using a telephoto lens with a hand camera be careful to hold the camera firmly : the least vibration will ruin the picture.
The tripod, though not a very important part of the outfit, should be selected with care. Be sure to have one that is sufficiently rigid ; the legs should telescope and the top be large enough to give the necessary support for the camera. Be sure also that the legs are well separated at the top that is to say, they must not come close together near the centre of the top ; if they do, the tripod will never be steady.
A word or two about plate-holders may not be amiss, as they are of vital importance. Never choose a holder because it is light. The lighter it is the less wood (if it is made of wood) is used, and consequently the less strength it has. Scarcely any of the plate-holders on the American market today are proof against half an hour of strong sunlight, while with most of them the plate would be hopelessly fogged if the sun shone on the holder for half a minute. Even the slides are not really opaque. If they are made of rubber they become soft in hot weather and brittle when it is cold. The paper slides are better, but they wear out quickly and do not stand dampness. The best kind are made of some preparation of celluloid. These are opaque, withstand any cold, but are apt to become soft while they are hot. Any plate-holder which does not allow of the plate being inserted and removed easily is not to be recommended, as we often have to change plates in the field, when the luxury of a dark room is of course unknown, and when buried in a sleeping-bag on a hot evening, we do not relish having to remove plates from a holder when they insist on sticking ; it is a test too severe for any one's patience.
From plate-holders we naturally turn to changing-bags. There are very few kinds on the market (except in England), and it is difficult to find one that is satisfactory. Most of them are good enough for a very short time, but they invariably leak if they are used for any length of time. If made of any material containing rubber, they are useless, as the rubber soon perishes. Of the materials which I have tried, pantasote seems the best. It is absolutely light-tight, and wears well. A simple form that answers for a changing-bag is a square box-shaped bag well rein-forced and bound on the edges. At each corner there is a loop to which cords are attached that will hold the bag in position ; two sleeve-like openings (with rubber bands to hold them closely about one's arm) on one side admit the arms, and should be made large enough to let the plate-holders enter. For a changing-bag this is all that is needed. Of course we cannot see what we are doing, but that is seldom necessary when once we know our plateolders.
A really portable field-developing tent is one of the much-needed things. At present there is nothing on the market in this country, though I understand one is about to be made. There are two patterns of these tents or boxes: one in which you put your arms inside, and with your head outside you look through a yellow glass window, another yellow or red window being on the opposite side. This has the advantage of coolness, but it is difficult to see very clearly. The other is a cloth and wood box or tent with a bag-like opening, which is tied round the waist, so that one's head and arms are inside. In cool weather this is all very well, but in hot weather it is frightfully uncomfortable for one's self and dangerous for the plates.
In going on a long trip it is well to be provided with a small quantity of concentrated developer, two rubber or celluloid trays, and a small red candle-lamp, in order to make a test negative once in a while to be sure that everything is going properly. Nothing can be more disappointing than to find after a long trip that through some small defect in camera or shutter all your work is spoiled ; and yet such occurrences are by no means uncommon.
The question of what plate to use is an important one, and one which every man must answer for him-self. Almost any of the good makes are good, and generally the complaints made against them are unfounded, those who make the criticisms being usually beginners who think it smart to find fault. For all work where colour-values require to be rendered accurately, isochromatic plates are necessary, the slower kind being most truly isochromatic. With gain in speed there is loss in their sensitiveness to the reds, greens, and yellows. Backed isochromatic plates are the ideal kind, combining as they do all the virtues of both the nonhalation and isochromatic properties. For sky effects they are perfect. Nonhalation plates are those which prevent the blurring around the strongly lighted parts ; as, for instance, a window from the inside of a room would be a blur with an ordinary plate, while with the backed or nonhalation plate the edges would be well defined. Ordinary plates will do well enough for snap-shot work, provided they are fast enough. It is well to remember that the more rapid the plate is the less latitude you have in exposure; in other words, the more rapid the plate the more nearly correct should the exposure be. For long trips where weight has to be considered, cut films are a good substitute for plates. These, as made by both Carbut and Seed, are really excellent, comparing favourably with glass plates. Their keeping qualities also are good. In using ray-filters — and the best of them are of coloured glass — always use an isochromatic plate ; the exposure is of course increased according to the density of the colour-screen. Over-exposure is a common error when the ray-filter is used. With a light-coloured glass and isochromatic plates the exposure is increased about four times with instantaneous plates, while with slow plates it is much less, as the slow isochromatic plates are so much more sensitive to the yellow light.