Interesting multiple exposures can be made with only one or two electronic flash units. Multiple exposure pictures, besides being artistic and interesting, are often used to study subject motion and position. This can be accomplished by the following procedures:
1. Darken the room and position your subject against a black background.
2. Allow enough background area for the number of different exposures you intend to make. When you
are using a ground glass camera, mark off on the glass, with grease pencil, the areas where the subject should be for each different exposure. If not using a ground glass camera, make a pencil sketch to help you position the subject.
3. Set up the electronic flash lights so the minimum amount of illumination falls on the background itself.
4. Turn off all room lights and make your first exposure. Then, without advancing the film, move your subject to the next position for the second exposure. Repeat this procedure for each image you want to record on the film.
PHOTOGRAPHING ACTION WITH ELECTRONIC FLASH
Action of any kind, no matter how slight, can add interest to most pictures. Each type of action requires a different camera technique, but because of the short duration of light from electronic flash, it is ideal for recording any action ranging from a fleeting expression to a sports triumph. Most electronic flash units have a maximum flash duration (the length of time the light is on) of about 1/800th second, and a minimum flash duration as short as 1/20000th second, thus you can freeze almost any action with the flash.
Indoors, where there is little existing light, you have no problem because the electronic flash itself stops the action; however, outdoors in daylight, you may encounter ghost images. Ghost images can occur when existing light and a slow shutter speed are used in conjunction with electronic flash. A ghost image appears as a blur when one image is recorded by the existing light and a second sharp image by the electronic flash.
ELECTRONIC FLASH AT NIGHT
Flash photography, outdoors at night, can produce very underexposed photographs if not taken properly. Outdoors, flash does not carry very far; therefore, it can be difficult to light objects from a distance; however, this limited coverage also gives you great control. Indoors, part of the output of a flash unit is reflected from the ceiling and walls back to the subject. Rarely do you find such reflective surfaces outside, so some light is lost. To compensate for the light lost, you must open up your aperture when photographing objects at any distance. Because so much light is absorbed in these large areas, it may not be uncommon to open up your aperture two or three f/stops. Tests should be conducted before shooting in large, indoor areas, such as gymnasiums and hangar bays or outdoors at night, to determine which flash, camera, and film combination produces optimum results.
At night a single on-camera flash produces stark lighting, and your subject is flatly lit and the background goes completely black. Close foreground details become very overexposed, and it is better to exclude them. Such simple lighting is ideal for action shots; for example, capturing leaping karate experts in midair at midnight. Subjects such as these benefit by being isolated from the background, but you may get more interesting lighting by using the unit off camera on an extension cord.
If the necessary flash-to-camera distance is greater than the length of your extension cord, use the open-flash method. Do not allow the camera to see the flash unit during the open-flash exposures.
Now that you have a basic knowledge of photo graphic techniques, it is important that you apply and practice the basic principles. Each and every time you pick up a magazine, book, or newspaper or watch TV or see a movie, you are exposed to various composition and lighting techniques. Study them and apply them every time you look through the viewfinder of a camera Remember, experiment with different camera angles to create interesting perspectives of your center of interest. Whether using available light or flash photography, notice what results the direction, intensity, and type of light have on your final product. Continual application and refinement of the principles of composition and lighting can greatly enhance the quality and aesthetic value of your photography.