With its space for five or more passengers, and with its low speed, the modern flying boat affords an excellent craft for photographic work. There is ample room for any size of camera, and for any style of mounting, if we assume that there is no objection to an opening in the bottom. The low ceiling of these ships, however, prevents their use for certain forms of aerial photography which should be of the greatest importance. Operations against shore stations—harbors, docks, shipyards, ships at anchor, and fortifications—cannot be undertaken for fear of anti-aircraft guns and hostile land planes. The solution of the problem of carrying and launching fast high flying planes from ships will immediately extend the usefulness of aerial photography to coastal work. In the recent war, such of this as was done, along the Belgian coast—the shore batteries, and the results of naval operations at Zeebrugge and Ostend—was done by land planes from territory held by the Allies. The photographic equipment of sea planes of the type suggested will of course present special problems, but the apparatus used will be apt to approximate closely to that of the land planes.
VII
THE FUTURE OF AERIAL PHOTOGRAPHY
CHAPTER XXXI
FUTURE DEVELOPMENTS IN APPARATUS AND METHODS
Prophecy is an undertaking that always involves risk. The prophet's guess of what the future will bring forth is based only on the tendencies of the past, the most urgent needs of the present, and the activity of his imagination. He may easily—and he usually does—entirely overlook certain possibilities which may arise apparently from nowhere and which profoundly affect the whole trend of development. Conditions which dominate at the present time—such as military necessity—may happily drop into the background and free the science from some of its severest restrictions. With this caution, some future possibilities in apparatus and methods may be presented along the lines already used in discussing the present status of aerial photography.
Lenses.—From the military standpoint the next steps in lens design would be toward telephoto lenses on the one hand, and on the other toward lenses of short focus and wide angle. The telephoto lenses used for spotting would be of long equivalent focus—a meter and more—but of handy size, that is, not more than 50 centimeters over all working distance. The wide angle short focus lenses would be designed for low flying reconnaissance or quick mapping work. They would also be demanded for peace-time mapping projects, where the largest possible amount of territory should be covered in a single flight. Both types of lens should be pushed to the extreme in aperture, for short exposures and the maximum of working days will always be demanded.
Cameras.—Peace-times will give the necessary opportunity to develop self-contained and therefore simply installed cameras. They will at the same time be made very completely automatic but simple to operate in spite of their complexity. Such cameras have, during the war, been the ideal of all aerial photographers, but the time has been too short since the necessary conditions have been understood for that lengthy development work and those complete service tests which are so necessary to develop all automatic apparatus. Several designs which are now being perfected may be counted on to take us a long way toward this ideal.
On the other hand, that military ideal which leaves the camera operator the greatest possible freedom for other activities, is apt to be entirely reversed in peace. The camera operator can now be required to be an expert, who will be free to change plates or filters and to estimate exposures, instead of giving his best efforts to the problem of defence. For him a simple and reliable hand-operated or semi-automatic camera is entirely satisfactory, and the great expense of complicated automatic apparatus has no longer its former justification.
Camera Suspension.—Perhaps the most pleasing prospect before the aerial photographer as he turns from war to peace work is that of having planes built for and dedicated primarily to photography. Instead of his camera being relegated to an inaccessible position, picked after the plane design has been officially “locked;” instead of yielding first place to controls, machine gun and ammunition; instead of being jealously criticised for the space and weight it takes up, the camera can now claim space, weight, and location suitable for any likely aerial photographic need. High speed no longer will be vital, and slower planes, permitting longer exposures in inverse ratio to their speed, will be chosen for photographic purposes.
A development which is sure to intrigue many investigators is the gyroscopically controlled camera. This has its chief raison d'être in precision mapping, whose possibilities from the air will undoubtedly be intensively studied at once. With the automatically leveled camera will come renewed attention to indicators of time, altitude, and direction, with the ultimate goal of producing aerial negatives that show upon their face the exact printing and arranging directions necessary to put together an accurate map.
Sensitive Materials.—Manufacturers of plates and films will direct efforts toward producing emulsions of good contrast, high color sensitiveness and high effective speed, especially when used in conjunction with the filters necessary for haze penetration. Exposure data will be accumulated and exposure meters appropriate for aerial work will be developed.