302.291X
Figure 13-8.–Hi8 video camera.
the camera to convert light rays into electrical impulses.
The cathode-ray tube converts the electrical impulses
back into light in the receiver (monitor).
CAMCORDERS
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 tempera-
ture 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
13-9
