In kite aerial photography (KAP), the camera is lifted with the help of a kite and is triggered either remotely or automatically to click aerial photographs. It is the art of taking low altitude pictures from a constantly moving platform without looking at the object directly. Hence, the results obtained are truly appreciated. The camera rigs used can range from extremely simple that comprise a trigger mechanism with a disposable camera, to complex setups using radio control and digital cameras.
In 1888, the first aerial picture was taken by Arthur Batut in Labruguiere, France. The kite's frame was made up of small rectangular sectional bars of hardwood. The crossbar was built by joining two sword blades together and was set at about 50 centimeters from the top end of the kite. In between the two bars, a box-shaped structure was connected to support the camera system. Two wooden bars were employed as fixing points for the bridle. The sail was made of strong paper strengthened with thin cotton cloth at the stress points. The camera was made of wood and cardboard and was loaded with 13x18 centimeter film plates. Rubber bands were utilized to trip the shutter which was activated by a burning fuse, so that after the preset altitude was reached, a photo was taken. The camera was attached using two supports that could be combined in different ways, to help the camera aim in different directions.
Camera Rig and Stabilization
The camera can be connected directly to the kite, but normally it is fixed to an adjustable rig which is suspended from the kite line at a distance from the kite. This distance subdues the excessive movement which is transmitted from the kite to the camera and helps the kite fly higher and into stable air. Usually the camera is adjusted to a high shutter speed to minimize motion blur. Normally for aerial photography, the suspension method is used, as it allows the rig to automatically align itself under the kite line, which further helps take photographs that orient perfectly with the horizon.
Shutter Release and Camera Positioning
Depending upon the type of camera and complexity of the rig electronics, there are different techniques to release the shutter of the camera. These techniques may comprise a radio controlled servo to press the release button, an infrared signal or wired connection to inform the camera to release the shutter, or a camera's inbuilt intervalometer. The camera fitted within a frame should have the rig designed in such as way that it can rotate horizontally and vertically and can change the picture format from portrait to landscape, by rotating the camera. Alterations in these angles can be made by manually setting the rig on the ground or by adjusting the rig using a remote control or an automatic controller in the rig while it is airborne. Normally a radio control system is used which has servos that readily adapt to adjust the rig positioning. Many automatic controllers have been manufactured that can click a photo, move the camera by a set angle, take the next photo, etc.
Single lined kites are the most commonly used kites as they are highly stable, provide very long line lengths and require minimum intervention from the flyer. But as the weight increases, particular designs with extra flying abilities, such as the flying angle, wind range, line pull, and ease of launch are considered. Some of the widely used designs are delta, rokkaku, parafoil, and the helikite. Out of all these, the simplest kite to employ for KAP is the helikite, as it is very light and flies in an extremely stable manner with or without wind.
With the arrival of the internet, light digital cameras, radio control, and microelectronics, kite aerial photography has become very popular. But the commercial use of KAP is restricted due to unpredictability of the weather (notably wind, sun, and rain) and the fact, that not every site is suitable for flying a kite. Hence, efforts to commercialize KAP have so far, been quite unsuccessful.