So, if the camera is way up on a kite line, the question is how to control it. We need a way to trigger the shots and maybe even a way to aim the camera. For many KAPers, designing and building these control systems is a fun and rewarding part of the whole KAP experience. And the variety of techniques they have invented is surprising. But, fortunately it’s no longer necessary to custom design a KAP control system. There are systems available to get anyone up and flying for a modest cost.
This article describes some of the more popular approaches to controlling KAP rigs and includes some advice on which types to use based on your own goals. If you’re the do-it-yourself type, this article may spark some ideas you’ll want to develop on your own. For everyone else, the article also includes descriptions of kits that can get you flying with minimal fuss.
KAP control systems tend to fall into one of two categories: automatic or remote control. An automatic system is one where the camera shoots photos at a pre-programmed rate. It may have the camera facing a fixed direction or it may change the camera orientation to cover more subject area. The photographer’s job with an automatic system is to adjust the rig before launch then get the rig into position to line up the shot he or she wants. This approach tends to produce a high volume of images since the camera is firing away constantly. Most of these shots turn out to be redundant or even useless. But there are almost always some gems mixed in with all the junk. Perhaps it’s just inevitable that out of several hundred images there’s bound to be a couple good ones. Or perhaps it’s because the view from a kite is so interesting that the camera always finds a nice shot. Whatever the reason, the automatic approach, or autoKAP as it’s frequently called, has proven to be surprisingly successful. And it has grown immensely in popularity in recent years.
The alternative to automatic controls, of course, is manual control with some sort of remote control system. Typically a model airplane R/C transmitter and receiver are adapted to a KAP rig. The receiver end of the radio link mounts on the KAP rig and controls servos to pan and tilt the camera. The shutter is controlled via a third channel, using a servo or one of the other shutter control mechanisms that were discussed in the previous article. Some rigs also incorporate a fourth R/C channel to switch the camera between portrait and landscape orientations.
The two approaches are quite different in terms of cost and skill required. Automatic systems can be very inexpensive and once launched require no interaction from the photographer. The photographer’s main job with this sort of system is to put the camera in the necessary location. If the photographer has a particular shot in mind, this means estimating the point of view the camera needs to have then moving the kite into position. Once the camera is lined up, though, it may require some patience since it could take a couple minutes to guarantee the automatic camera motion has shot the needed orientation. On the other hand, if the goal is to capture numerous scenes of a large, scenic area a good strategy is to simply set the KAP rig in motion and take a stroll through the area of interest. The rig will shoot away capturing many interesting features from different angles.
Remote control systems for KAP occupy the medium to high price range for KAP systems. But, while more expensive than most automatic systems, their prices aren’t out of reach of most photographers. These systems demand a little more skill on the photographer’s part. In addition to putting the camera in the right location to get a shot, the photographer needs to aim and fire each shot. Pan and tilt controls are typically mapped to one or two joysticks on an R/C transmitter unit. Using these controls, the operator watches the camera and guesses where it’s aiming. People with experience at this recommend taking multiple exposures of the intended subject shooting above, below, left and right of the initial guess.
Keep in mind that while working on aiming the camera, it’s still necessary to pay attention to the kite to keep it flying safely. The kite always requires one hand and sometimes both, too, so the R/C transmitter needs to be set up to operate with one hand and may need to be laid aside at times. Some users of R/C equipment have found ways to modify or repackage the transmitter to make it easier to hold and operate with one hand. Still others find that it’s best to have two people working as a team – one handles the kite and the other handles the camera controls.
Since aiming the camera properly is key for certain types of KAP photography, some people have incorporated video feedback systems into their setups. This amounts to a tiny video transmitter on the KAP rig that sends a signal to the ground. The operator, then has a matching receiver and some sort of display that shows the view from the camera. These systems, while providing excellent aiming capabilities, also bring some drawbacks, though. For one thing, many types of displays are difficult to view in field conditions such as full sunlight. So the video monitor is usually equipped with some sort of sun shade the operator can put their face in. But if too much attention is placed on the video display, there’s a real danger of neglecting the kite or other hazards in the surrounding environment. Many who try video systems have bad experiences with them and give them up. Others, though, consider them indispensable. The ones who find success with them are more often the same people who KAP in two-person teams. With one person managing the video and camera controls, that still leaves one person with their full attention on the kite and the surroundings.
Besides the automatic / remote control distinction, another way of classifying KAP rigs would be according the degrees of freedom they offer for orienting the camera.
The “classic” camera control setup is one that allows the camera to rotate on two axes: pan and tilt. Panning the camera moves the view around the horizon. Tilting moves from the horizon to the nadir, a point directly below the camera. With control over these two axes, the camera can be aimed at any point on the ground. The pan/tilt arrangement is the most common setup for remote control rigs, by far. Some automatic KAP systems also use this arrangement.
Some remote control rigs incorporate a third degree of freedom that rotates the camera from a portrait orientation to landscape orientation. This is useful for composing shots for horizontal or vertical display. For this reason, this feature is often referred to a Ho/Ver (pronounced “Hover”) switch or Ho/Ver axis.
As mentioned above, some automatic KAP systems feature the same pan and tilt controls that remote control ones use. But automatic KAP systems with just one or even zero degrees of freedom for aiming are also popular. For example, the popular BEAK kit from Brooxes.com is an automatic control system that moves the camera in the pan direction but not tilt. The operator can set the tilt angle to any desired position before launch but it doesn’t change in flight. If tilted to shoot the horizon, the camera continuously spins taking pictures in different directions. If tilted toward the ground, the rig photographs a circular area below the camera repeatedly.
Automatic KAP rigs with no motion controls are not uncommon either. There are rigs where pan and tilt can both be set on the ground before launch. Once airborne, these rigs continue to shoot in one direction indefinitely. This is useful for situations where the camera angle relative to the subject and lighting conditions is known. And there are rigs that are set up to shoot straight downward repeatedly. These offer no variation in shooting angle but they are useful for surveying the ground in some applications.
So far all the discussion has been about electronic control systems. That’s fair since the vast majority of KAP work is done with electronic controls, but there are other options.
Mechanical control systems are almost exclusively automatic in nature. They range from simple to sophisticated in their ingenuity. On the simple end of the spectrum are the single-shot systems using rubber bands or melting ice to trip the shutter just once before requiring a reset. On the sophisticated side, there are wind-driven mechanisms that synchronize shooting the camera with pan and/or tilt motions. Spring driven systems using a music box mechanism have also been built. But all of these mechanical control systems are quite rare compared to their electronic counterparts.
[TODO: Consider moving discussion of triggering options to here.]