The ideal of every military photographic service has been an automatic or at least a semi-automatic camera, in order to reduce the observer's work to a minimum. Yet as a matter of fact almost all the aerial photography of the Great War was done with entirely hand-operated cameras. The primary reason for this was that no entirely satisfactory automatic cameras were developed, cameras at once simple to install and reliable when operated. Even the propeller-drive semi-automatic L type of the British Air Service was very commonly operated by hand, for many of the pilots and observers regarded the propeller merely as another part to go wrong.
Any automatic mechanism in the airplane must work well in spite of vibration, three dimensional movements, and great range of temperature. The requirements were well recognized when the war closed, but had not yet been met. Careful study of the conditions and needs by competent designers of automatic machinery may be expected to result at an early date in reliable cameras of the automatic type, but the description below of hand-operated cameras really covers practically all the cameras found satisfactory in actual warfare.