Kite Aerial Photography Electronic Resources--Articles-Hard Knocks2-KAPR

[Home]

Lessons Learned from the School of Hard Knocks
Page2
(Continued)
By Ed Johnson
Wayne, Nebraska, USA
June 5, 2000

                      PAGE 1
Introduction
I. Kites
II. Line

                      PAGE 2
III. Camera
IV. Lenses
V. Film
VI. Attaching and controlling the camera

                      PAGE 3
VII. Subjects
VIII. The Process (from launching to landing)
IX. Investments and Accessories

III. Camera
Because kites can come down as quickly as they go up, you’ll want to avoid making a large investment in your camera. You’ll probably want to find one with a plastic rather than metal body--it’ll be lighter, less expensive, and more forgiving when it crashes. Because you can leave your camera focused at infinity, there’s no need for an auto-focus camera. But because clouds do come and go, it’s nice to have auto-exposure. Another issue is finding a camera that has a convenient shutter release that can be tripped while you’re not around.
I use two 35 mm cameras. My first choice is a Pentax ZX-M. It has manual focus, which costs less. It also has an optional electronic shutter release that I’ve connected to a servo meant for a radio-control airplane. Because of its common bayonet mount, it’s easy to find a variety of less expense lenses. Finally, I’ve been very impressed with the way it has held up to the abuse it’s received while dangling from a kite line.

My second choice is a Rollie Prego 90. Its chief advantage is that it has an intervalometer that automatically takes a photo from once every ten seconds to once an hour. This eliminates any other equipment needed to trip the camera’s shutter. It has disadvantages, though. For one, the zoom lens is no wider that 28 mm (the disadvantages of this are discussed under lenses).For another, pictures are taken at set intervals, regardless of where the camera may be swinging at that moment. And it does have many features not needed for KAP, so it is more costly.
                       Rollei Prego 90

Pentax                         Pentax ZX-M

Lessons Learned from the School of Hard Knocks
Page2
*(Continued)*
By Ed Johnson
Wayne, Nebraska, USA
June 5, 2000
PAGE 1 Introduction I. Kites II. Line PAGE 2 III. Camera IV. Lenses V. Film VI. Attaching and controlling the camera PAGE 3 VII. Subjects VIII. The Process (from launching to landing) IX. Investments and Accessories III. Camera Because kites can come down as quickly as they go up, you’ll want to avoid making a large investment in your camera. You’ll probably want to find one with a plastic rather than metal body--it’ll be lighter, less expensive, and more forgiving when it crashes. Because you can leave your camera focused at infinity, there’s no need for an auto-focus camera. But because clouds do come and go, it’s nice to have auto-exposure. Another issue is finding a camera that has a convenient shutter release that can be tripped while you’re not around. I use two 35 mm cameras. My first choice is a Pentax ZX-M. It has manual focus, which costs less. It also has an optional electronic shutter release that I’ve connected to a servo meant for a radio-control airplane. Because of its common bayonet mount, it’s easy to find a variety of less expense lenses. Finally, I’ve been very impressed with the way it has held up to the abuse it’s received while dangling from a kite line.	My second choice is a Rollie Prego 90. Its chief advantage is that it has an intervalometer that automatically takes a photo from once every ten seconds to once an hour. This eliminates any other equipment needed to trip the camera’s shutter. It has disadvantages, though. For one, the zoom lens is no wider that 28 mm (the disadvantages of this are discussed under lenses).For another, pictures are taken at set intervals, regardless of where the camera may be swinging at that moment. And it does have many features not needed for KAP, so it is more costly. Rollei Prego 90 Pentax ZX-M

IV. Lenses
Here are five suggestions about lenses: A. Get as wide an angle lens as possible. This is generally designated by a shorter focal length. For example the 18 mm lens on my Pentax is shorter (and therefore wider) than the 28 mm lens on my Rollie. There are two good reasons to want a wider-angle lens. First, the shorter the lens (that is, the wider the angle of view), the less obvious is the blur of camera movement. When you see the way your camera can swing from a kite line, you’ll want the advantage of a wide-angle lens to ensure getting sharper images. The second reason for a wider-angle lens relates to the fact that distances can be quite deceptive. When your camera’s several hundred feet away, it’s difficult to calculate precisely where it is in relationship to your subject. The wider the lens, the closer the camera can be to your subject and the surer you are of including that subject in your photos. Besides all this, the perspectives seen from wide-angle lenses are more dramatic. The widest are the fish-eye lenses. Their view covers 180 degrees, their images are extremely distorted, and their prices are quite high. It seems they’re more popular among kite fliers in the Orient than here. B. Get a fast lens (one that lets more light pass through it). Lens speed is designated in f-stops--fractions of a lens’s focal length. For example, an f/2 lens lets more light through it than an f/4 lens does. The logic of wanting a faster lens is simple: the faster the lens, the faster the shutter speed, the less blurry your pictures will be. The drawback is price. It’s common for a lens that lets in twice as much light to cost ten times as much. By the way, a lens is typically sharpest when it is closed down two or three stops. For example, an f/2 lens may be sharpest when it’s closed down to f.4 or f/5.6.	C. Avoid zoom lenses. They tend to vignette (that is, to produce pictures that are darker on the corners than the center), they tend to be slower (that is, let less light pass through), and historically they tended to be less sharp than fixed focal-length lenses. On the other hand, you might find a zoom to be your least expensive lens. D. Consider using no-name lenses. For your KAP photos, you may notice no difference in image quality. I put my camera on a tripod to shoot identical scenes on fine-grain Kodachrome 25 slide film--half the roll with an 18 mm Nikor lens and the other half with a store brand lens. When I viewed the results, I couldn’t tell the difference. If there’s no significant loss of image quality, I’d just as soon see my $200 lens than my $800 lens swinging a thousand feet away. E. Get a filter. I keep a broken filter that reminds me of how much cheaper it is to be replaced than its lens. A cheap UV filter that filters out ultra-violet light works fine. You may want to try a polarizing filter to make color more saturated. Drawbacks with polarizing filters are that they let less light through, they cost more, and their effect on the sky is not uniform. Broken UV Filter

V. Film
What type of film to use depends on your KAP goals. Negative film is more forgiving about bad exposures and it produces good prints. But it’s easier to store and view 20 slides on a single plastic page, and once upon a time slides were known for making better reproductions. For archiving images, Kodachrome slides should have the least color change over time. Another issue is film speed. Generally, the slower the film, the finer the grain, the better the enlargement. On the other hand, the faster the film, the faster the shutter speed, the less blurry the image. The goal is a compromise between grainy high-speed film and blurry slow speed film. Thankfully today there are many excellent high-speed films. I’ve been happy using Kodak Gold 400 film.	Film length is another factor. Once you’ve launched your camera, it’s nearly impossible to keep track of how many photos you’ve taken. Typically I try to take a photo every hundred feet as I let out and take in the line. I generally find a 24-exposure roll to be about right. Processing will likely be more important than the film itself. I’ve had more success with Kodak processing than with local processors.

VI. Attaching and controlling the camera
Once you have the other essential elements (e.g. kite and camera), you need some way of attaching the camera to the line and controlling it. A. Attaching the camera. One of the big challenges of KAP is getting a stable platform on which to mount your camera. Today there seem to be two principal methods. One is a pendulum, generally an aluminum frame that swings from a clamp attached to your kite line. Some crafty people cut, drill, and bend their own into shape. I bought mine from Into the Wind for about $60. Pendulum KAP Rig The alternative is the Picavet, which is an elaborate system of pulleys and line. It’s meant to provide a more stable platform than a swinging pendulum. I made mine from parts I found at our local hardware store. They’re adequate but heavy. As a basis for my picavet camera mount, I used Ralf Beutnagel’s drawing and description in the now defunct Aerial Eye (vol 1, no. 5, fall 1995, pp. 6, 18). The model I used is pictured, with its line run in the following order: A1 - 1 - B1 - Ring -4 - A2 - Ring - 2 - 2B - 3 - A1. Even with this elaborate system, my camera was still tossed about by the wind, and I’m not convinced it’s noticeably better. Picavet I’ve tried other ways of attaching a camera, but with little success. For example, I’ve attached a small camera with a timer to the horizontal spar. One problem with this is that it affects the balance and stability of the kite itself. Another problem it the limited view from this position. I also tried attaching a camera between the kite and the tails. This so through the kite off balance that I wasn’t even able to launch it. Camera Mounted on DC Spreader Remember that with ground turbulence, a low flying kite can come down just as quickly as it goes up. For that reason, I wait until the kite’s at least a hundred feet up before I attach the camera.	B. Controlling the camera. Once you have your camera attached, you need to control how to trip the shutter and where the camera’s pointed. There are a number of ways to release the shutter. Most involve some kind of timers. (One person uses a melting ice cube.) The problem with timers is that you never know where the camera will be when the picture’s taken. I prefer using a radio control device to trip the shutter. There are several expensive models made for cameras, but few if any have a range of a thousand feet needed for KAP. On the other hand, the remote control equipment for model airplanes seems to be much less expensive, and as one clerk told me, can control a model that’s flown nearly out of sight. I’ve found a simple Hitec model RC kit on sale and have been happy with it. This kit contains two servos that would normally control the model’s flaps. Instead, I use one to push the camera’s shutter release. The only drawback I’ve found is that the joystick on the control is meant to move the model plane’s rudder right or left and the tail flaps up or down. That means any one of these four directions could be used for my shutter release. On mine, moving the stick to the left trips the shutter. So I won’t forget, I’ve put a left arrow on masking tape next to the stick. Originally I tried to use the second servo to pan the camera (that is, make it turn right or left). RC Transmitter Some people have more elaborate systems that also control the tilt (up and down movement). The problem I had with this is that even with the aid of binoculars, I couldn’t tell which way the camera was pointed once it was a few hundred feet away. I found it better to use a simpler mount with thumbscrews that allow me to tighten the pan and tilt angles of the camera before I launch it. I now first picture where my camera will be and which way it needs to be pointed once it gets there. I then take a series of pictures at different distances. I usually get at least a few pictures per roll with the view I imagined. This ability to visualize scenes only improves with practice. Manual KAP Rig

PAGE 1 PAGE 2 PAGE 3