As a nonspecialized Photographer's Mate without a motion-media NEC 8143, you will be concerned mostly with recording motion-video images using a single camcorder. A camcorder has a single VTR directly attached to the camera to form a camera and recorder unit.

Each camcorder comes with manufacturer's instructions on how to use the equipment. Because there are a great variety of camcorders in the Navy, you must consult the instruction manual supplied with your machine for best results. One common motion-video camera used in the Navy is the Hi8 video camera (fig. 13-8).

The Hi8 camcorder is a small camera-VTR unit that records amazingly high-quality pictures and sound compared to a video home system (VHS) camcorder. It uses a special 8mm (about 1/3 inch) cassette with metal-oxide coated tape. These tapes are similar in size to an audio cassette tape.

A tempting practice while operating a camcorder is to shoot all videotape in the automatic mode. On the Sony Hi8 camcorder, when the AUTO LOCK switch is set, the iris, focus, white balance, sensitivity, and shutter speed (1/60) are set and adjusted automatically. If left unnoticed, there are several circumstances under which the AUTO LOCK mode will produce poor or undesirable results. You, as the camera operator, must pay attention to the subject and the surrounding situations to produce quality motion-video coverage; in particular, brightness levels, focusing, color temperature of the light source, and subject movement.

Brightness Levels

The single greatest influence on picture quality is the brightness level. When the brightness level is too low, the recorded image looks grainy and flat. By familiarizing yourself with the brightness level of the subject, you can improve your recordings tremendously. In situations where the light level exceeds 100,000 lux, such as snow-covered scenes or a beach scene on a clear summer day, an ND filter is required. Under other daylight and bright, indoor conditions, the automatic iris is capable of adjusting to provide excellent results; however, in a low-light situation, such as spaces onboard ship, auxiliary lighting may be required to provide clear, sharp images. Another alternative, when available on your camcorder, is to increase gain. By increasing the gain, you increase the level of amplification of the video signal. This increases the contrast and provides a higher-quality recorded image.

In some situations, such as high-contrast scenes or backlit subjects, you must adjust the iris manually. Just like the aperture on a still camera, when the subject is backlit, open up the iris. When the subject is too bright, you must close down the iris.

Manual Focusing

There are situations when you must manually focus the camcorder to obtain sharp images. In the autofocusing mode, the system uses a sensor at the center of the viewfinder screen to adjust the focus automatically; therefore, in situations where there is insufficient light, the subject is strongly backlit, or with subjects consisting of flat colors or little contrast (such as bulkheads or the sky), the autofocusing mode may not function accurately.

Other situations in which you should use manual focusing are as follows:

When the subject has finely detailed repetitive patterns

When one subject is close to the camera and another is far away

When the subjects are located behind screens, nets, or frosted glass

When objects pass between the camera and the primary or intended subject

When using lenses or filters to create special effects

You may also want to use manual focusing to conserve battery power.

CAUTION

NEVER attempt to force or manually focus the focus ring when the camera is set in the autofocusing mode. This may damage the camera.

White Balance

Usually the auto white balance function of a video camera operates sufficiently in the automatic position; however, there are situations when the automatic light balance may not work correctly. Some of these cases are as follows:

When the light reflecting from the subject is different from the light that is illuminating the camcorder

When shooting a monochromatic subject or the subject is against a monochromatic background

When recording under a sodium lamp, mercury lamp, or a white fluorescent lamp

When recording outdoors under neon lights or fireworks

When shooting scenes just before sunrise or right after sunset

To white balance a motion-video camera manually, you can follow a simple procedure. Normally a white lens cap, made of a diffuse plastic material, is supplied with the camera. You also can use any white object to white balance the camera, providing the white object is illuminated under the same conditions that you will be shooting. To white balance, you simply place the white lens cap over the lens, point the camera at the light source, and press the white balance button. Remember, when in the manual white-balance mode, if the color temperature of the light changes, you must reset the white balance.

To create special effects, there may be times when you want to lie to the white balance sensor; for example, you may want to produce motion video that has a warm color balance, such as that which occurs at sunrise or sunset. To produce video coverage with warm characteristics, you can "white balance" the video camera on a blue object or any of the complimentary colors. When you record the scene, an overall yellow cast is produced. You can also use filters to create various effects.

Shutter Speed

When the Hi8 camera is set in the AUTO LOCK position, the shutter speed is set at the normal speed of 1/60 second. When fast-moving subjects are recorded at the normal shutter speed, the pictures are not recorded clearly. You can improve the image quality by increasing the shutter speed.

Because more light is required when shooting at higher shutter speeds, you should not try to shoot fast objects under poor or low-lighting conditions. Outdoors on clear days, you can record fast-moving subjects at shutter speeds of 1/2000 to 1/10000. On overcast days, shutter speeds of 1/250 to 1/1000 are recommended. While handholding the camera indoors, you may want to provide a more stable image. In this case, a shutter speed of 1/100 is recommended. Do not use a shutter speed of 1/250 or higher indoors unless you use additional artificial lighting.