1-2 Operating the Camera
Loading the Digital Camera With Recording Media
A digital camera uses one of several systems to store both the recorded digital images and their associated sound files. These include:
The image capacity (the number of images than can be recorded until the drive is "full") of the storage media depends on more than just the megabyte capacity of the PCMCIA card itself. For example: a 520 MB PCMCIA card can normally record 150 to 200 images but this number is greatly reduced when sound files are added. (Many DCS have sound-file recording capability, feature that allows the journalist to record information (a "tag") pertaining to a particular image.)
To keep your camera serviceable you must ensure that it retains sufficient recording capacity. When you return from an assignment, you will normally upload the data files from your PC card into a computer for processing and delete the files from the card thus restoring its original recording capacity. If this cannot be accomplished, you may need to use the cameras image delete feature to make room for new images or replace the used card with a fresh one.
Powering Your Camera
Electronic Flash. Electronic flash operation requires a power source. Power is usually supplied by replaceable (usually, AA or AAA alkaline) or rechargeable batteries of appropriate type and quantity placed in the battery compartment of the flash unit. An external battery pack connected to the camera/flash unit by a flexible power cord may also be used. Consult the owners manual for specific requirements and instructions. It is a good practice to begin an assignment with fresh batteries and to carry spares.
35MM SLR Cameras Some older cameras are manually operated and do not require an electrical/battery power source. However, many modern 35MM models have battery-operated components. Consult your OM for specific details.
Digital Camera Systems DCS operation requires a reliable source of power. Automation of camera setting adjustments, recording and downloading digital images and audio tags all require power. All professional DCS have a visual display that let you monitor the condition of its power supply. Power sources and configurations for most professional DCS include
Integral battery. Usually considered non-removable in normal service, these are recharged between assignments with an AC battery charger/adapter connected to a commercial power source or generator. Given an electrical source/outlet at the shooting location, the battery may be conserved and the AC adapter feature used to power the camera. Note: DCS currently approved for Army PA units do not use an integral battery.
Replaceable battery (Figure 1-7). The primary source of power for DCS approved for use by Army PA units is the replaceable and rechargeable NiCAD, NiMH or LiO battery pack. While fully charged battery can power approximately 300 images, use of the liquid crystal display (LCD) to preview stored images reduces this number appreciably. Approved DCS have a design feature (access door) which permits easy replacement in the field (Figure 1-8). Check the OM to ensure that the battery pack is appropriate for your DCS.
Battery charger (Figure 1-7). The battery charger consists of a battery receptacle and an electrical transformer which reduces the voltage from a commercial source, automotive power outlet or generator to the voltage required by the charger. Ensure the battery charger Check your equipment documentation for user instructions and equipment limitations.
AC Adapter (Figure 1-9). AC voltage adapters convert electrical power from an available external source (input) to a voltage that can be used (output) by your camera. You may want to use it to conserve the battery when shooting indoors. It also ensures a reliable source of power when downloading images from the camera into the computer. In North America, 110 volts AC is the commonly supplied house current, drawn from the two- or three-hole wall sockets common in our homes and offices. However, there is no international standard. Many other voltage and plug configurations exist. (Great Britain uses a 210-volt system and four different types of plugs!) Your kit (Figure 1-10) must contain plugs or cables configured for your area of operation. Some general rules-- Use only the AC adapter designed for your camera. Use only the type(s) of power source indicated on the adapter; a line voltage outside this range can destroy the AC adapter and the camera. Never plug other adapters into the camera or use the AC adapter supplied with your camera for any other purpose. Consult your operators manual (OM) for specific instructions concerning use of the AC Adapter.
Freezing the Action
Why would you want to increase the shutter speed? One reason would be that you have too much light -- even though your aperture is on the smallest setting. Shooting photos at a beach or on a snow-covered mountain would call for a high shutter speed.
Another advantage of high shutter speeds is that they tend to freeze the subject. Your pictures can suffer from "camera shake" if you are not using a tripod to hold the camera still. One way to get around this problem is with a high shutter speed. Besides camera movement, you may have the problem of subject movement. Sports pictures often call for a higher shutter speed to freeze the subject in mid-action. To photograph moving objects, a shutter speed in excess of 1/125 second is ordinarily required. Direction, distance from the subject and speed of movement are factors in determining correct shutter speeds. A distant object moving toward you would not be blurred as easily as a nearby object moving from left to right at a high rate of speed -- more factors equal higher shutter speed.
Another reason for using a high shutter speed might be to allow for a large aperture (f/1.8, f/2 or f/2.8). Large apertures lessen the "depth of field," causing the background to soften or blur. This is called "selective focus" and is useful in eliminating background distractions.
Getting it in Focus
A camera is focused by moving the lens closer or farther from the film (or focal) plane. On professional 35mm cameras, the lenses are mounted on a threaded mount that permits precision movement of the lens by rotating a ring or some similar device. On many DCS, this is done electromechanically.
Modern 35mm and digital cameras
Many modern 35mm cameras and all professional digital cameras have design features, which permit a choice of several automatic and manual focus control options. Automated shooting modes offer convenience and allow the photographer to provide a useable product that captures candid, unposed action. However, expert manual adjustment and control of each focus element yields consistently better products. Therefore, use manual options when the nature of the shooting assignment permits planned shots or careful measurements.
There are aids that are used to help obtain correct focusing:
Study the OM description of the focusing aids for the camera you will use.
Depth of field
Because of the laws of optics, a smaller aperture means that more things will be in focus in a photograph. In the example of f/16 at the beach, not only would the horizon of the ocean be in focus, but so would the sand bucket sitting three feet in front of the camera. The distance between the closest object in focus and the farthest object in focus for a given lens focal length and f/stop is called the "depth of field" (see Figure 1-11). Most 35mm SLRs and DCS have a depth-of-field scale incorporated in the distance scale. By using it properly you can set the camera to best advantage. (Example -- You are shooting at f/22 with a 55mm lens. The depth-of-field scale shows you that you can get everything in focus from five feet to infinity.)
Figure 1-11. Depth of field
Because of the laws of optics, shorter focal length lenses (wide angle - i.e. 28mm) have greater depth of field than long focal length (telephoto - i.e. 135mm) lenses. A short focal length lens with a small aperture gives maximum depth of field.
When you don't have as much light to work with you may have to open your aperture (use a larger f/stop - i.e. f/2.8). On a dark, stormy day at the beach you would be lucky to get the shore and the horizon both in focus, because instead of f/16 you might be using f/3.5.
In photography there are trade-offs. As the aperture size is decreased to increase the depth of field then the shutter speed must be decreased (see Figure 1-12).
Figure 1-12. Depth of field vs. action-stopping capability.
On a stormy day at the beach you could still have a large depth-of-field if you used a slow shutter speed like one second. But a moving boat would be nothing but a blur because of the slow shutter speed. One way to solve this problem would be to use a film that is more sensitive to light or a higher ISO if you are using a digital camera. High-speed films (usually classified as ASA/ISO 400 and up) can be used to solve the problem of low light levels. A high-speed film doesn't need as much light for a proper exposure. Here, too, there is a trade-off. Higher-speed films are "grainier" than lower-speed films. Through a magnifying glass every photograph can be seen to have a granular pattern. In high-speed films this grain pattern is more pronounced. Using higher ASA/ISOs with a digital camera can result in some shift or loss of color values. Another quality of film called "sharpness" (not to be confused with focus) can also be related to film speed. Generally speaking, the slower films and lower ASA/ISOs will give more accurate reproduction of a subject.
Design: David L. Heiserman
Publisher: SweetHaven Publishing Services
Copyright © 2007, SweetHaven Publishing Services