Journalists routinely illustrate their news and feature stories with photographs. A well-composed photo can catch the readers eye and add vitality, realism and interest to a story. A single moment of visualization not only replaces wordy descriptions but also adds credibility and often excites and emotionally involves the reader in the storys details. Some of the best stories are told almost entirely by pictures. As a journalist, it is important for you to understand the fundamentals of photography. Well begin this lesson with some background information about the photographic equipment you are likely to encounter.
The old. For most of the last century, the basic tool of the military photojournalist had been a single-lens reflex (SLR) camera loaded with the roll or cartridge of 35mm film best suited to a particular photographic assignment. The photographer considered the amount of available light, type of subject being photographed, and the desired resolution (detail) required in the final product. For most newspaper and magazine work, fast, ASA or ISO (International Standards Organization) 400 films, such as Tri-X 400 or T-Max 400, were chosen. Specialized films, such as the slow ISO-40 or medium-speed ISO-125 for use in bright lighting conditions to the extremely fast ISO-3200 for use in subdued light were also available. Because photographic resolution (photo quality) decreased as film speed increased and images were enlarged, quality photography required a balancing act among film choice, camera settings, the chemicals and timing involved in the "wet" film development process and photo enlargement operation. The enlarged paper photograph was cropped for content and sizing. Occasionally, airbrushing or other techniques were used to enhance or remove small imperfections from the enlarged print. The finished print was then processed by the printing activity for reproduction at their facility.
While photographers often processed their own film for local use, in many cases the prints or cartridge of exposed film was simply sent via courier service to a remote location.
The new. The final decades of the last century saw advances in servo-mechanics, microelectronics and computer technologies applied to 35mm camera design.
Todays military photographer uses information age tools of digital photography. Digital cameras employ the same optical principles as their earlier 35mm cousins. Many use the same assortment of lenses, filters and flash accessories. Some can record sound. While portions of their operation may be automated, the photographer must still ensure that camera settings and focus are appropriate. The assortment of levers, dials, pointers and mechanical controls associated with manually operated cameras have been replaced by electromechanical servos, liquid crystal displays (LCDs) and push-buttons. Professional digital cameras also feature "shooting modes" or computer programs that can automate all or a portion of the focusing operation. However, the greatest difference is that digital cameras incorporate programmed microchips and circuitry, called "firmware." Firmware programs automate the cameras operation and enable it to "talk" to another computer." At the heart of the digital camera, working in conjunction with the firmware, is the "charge-coupled device." The CCD is a special light-sensing chip that electronically converts the light and dark color values comprising a picture into a digital image. The image is recorded on either a built-in hard drive or removable PC card instead of film. There is no with toxic chemical disposal problem since none are involved in processing digital imagery.
In addition to the reflex viewfinder used by the photographer to aim the camera and compose the picture, many digital cameras incorporate a small monitor screen and control mechanism, which permits viewing recorded images and deleting those that are unwanted. Because of the cameras use of electronics and automated adjustments, the photographer must ensure an adequate power supply.
The recorded images are uploaded into a computer where they may be viewed with specialized image processing programs that permit you to enlarge, crop or enhance the digital images. The 35mm (diagonal measurement across a 35mm film negative) is an industry standard; digital photography emulates this standard. After the images have been processed, they may be imported into a desktop publishing program and positioned on an appropriate page or electronically transmitted to remote users for further processing or publication.
In summary. The "basics" of still photography havent changed. The techniques of digital photography, in terms of picture composition and camera setting and exposure requirements are the same as those used in "wet film" photography. Because specific camera features, power requirements and location of camera controls vary by manufacturer and model, you must study the operating instructions or owners manual for your particular camera.
This lesson uses the Canon F-1 35mm SLR and Kodak DCS 520 digital cameras as instructional referents.
Familiarize Yourself with the Camera.
You should inspect the camera and familiarize yourself with its controls. Learn how they operate. Figure 1-1 shows the location of the Canon F-1 35mm SLR camera controls and indicators. If possible, obtain a camera, similar to the F-1 for examination and familiarization during this subcourse.
Figure 1-1. 35mm SLR camera
Lenses and Apertures
Most professional SLR and digital camera systems have interchangeable lenses. The "focal length" of a lens is the distance from the optical center of the lens to the focal plane (film/CCD plane), when the camera is focused upon an object at infinity. Focal length determines the size of the film/CCD image. A 50mm focal length lens is considered the "normal" lens because when you look through the viewfinder objects appear at their approximate normal size. A smaller than normal focal length (like 28-35mm) provides a wider angle of view. However, objects will appear smaller than normal. A telephoto lens has a longer than normal focal length (135mm) which, like binoculars, makes objects appear larger than normal. Zoom lenses (35-105mm or 80-200mm) are designed with adjustable focal lengths.
The lens has "f/stops" or diaphragm aperture settings (see figure 1-1) which includes the numbers 3.5, 4, 5.6, etc. These control the amount of light passing through the lens and striking the film or CCD. The higher the f/stop number, the smaller the amount of light allowed to enter the camera lens. Aperture f/5.6 lets twice the amount of light strike the film as aperture f/8. Another way of saying it is that f/5.6 is "one stop larger" than f/8. Click stops between the apertures are "half stops." F/stops can range from f/1.4 to f/22; the larger the number, the smaller the aperture. The f/stop is always read as a whole number, not as a fraction or ratio. The meaning of "f/8" is that the diameter of the opening in the diaphragm is one-eighth of the lens' focal length (Figure 1-2).
Figure 1-2. Diaphragm
o General. The camera shutter is an adjustable mechanism that can be opened and closed for predetermined lengths of time to regulate the amount of light permitted to pass through the lens. The shutter speed control on the 35mm camera (see Figure 1-1) is usually a dial with a scale that includes the numbers 500, 250, 125, 60 etc. Shutter speeds control the duration of time (usually, fractions of a second) that light is allowed to pass through the lens aperture to reach the film. The shutter speeds usually range from 1/1000 of a second to one second or more. Unlike aperture settings that can be set between the marked f/stops, there are no intermediate shutter speed settings on a manual camera.
Each marked shutter speed admits one-half or two times the light of the adjacent speed. 1/125 second lets in half the light that 1/60th second lets in. 1/125 second lets in twice the light that 1/250 second lets in. A lot of light will get to the film when the shutter speed is slow. Shooting without a flash, hand-held photography of stationary objects requires a minimum shutter speed in order to prevent "camera shake." "Camera shake" is especially noticeable in photographs taken with telephoto lenses (ever try to look through a powerful telescope without a tripod?). To prevent it you should choose a shutter speed close to the focal length of your lens. Example: a 50mm lens could be hand-held at 1/60 second...a 135mm lens could be hand-held at 1/125 second. If the camera is mounted on a tripod or a steady support, speeds of less than the recommended speed can be used.
o Digital Camera Systems. Professional DCS (and many advanced 35mm cameras) have design features (programs) that electronically control and coordinate shutter speed and aperture value (f-stop). This permits the photographer to select a shooting mode appropriate to the particular assignment or shooting conditions. For example, the Kodak 520 DCS provides the following six modes.
Program AE Mode. In Program AE mode the camera automatically sets the Shutter speed and aperture value according to the subject brightness. This mode allows anyone to start capturing images quickly without worrying about exposure settings. Five focusing points provide a wide focusing area, making it easy to try out various picture compositions.
Shutter-priority AE. In this mode, you set the shutter speed and the camera automatically sets the aperture according to the lighting conditions.
Aperture-priority AE. In this mode, you set the aperture and the camera automatically sets the shutter speed according to the lighting conditions.
Depth-of-Field AE. This mode places everything between two points, one in the foreground and one in the background within the zone of focus, effective for making sure everyone in a large group picture or everything in a landscape photo is rendered sharp. After you designate the near and far points in the scene, the camera automatically sets the optimum focus position and the aperture necessary to achieve the required depth of field, then sets the shutter speed to achieve the correct exposure. The near and far points can be designated using the selected focusing point in Manual Focusing Point Selection mode, or using the center point in Automatic Focusing Point Selection mode.
Manual Exposure. This program mode lets you set both the shutter speed and aperture. Use this mode when you need complete control of exposure for creative effects or when using a hand-held exposure meter. The Main dial sets the shutter speed and the Quick Control dial sets the aperture.
Bulb Exposure. The shutter stays open for as long as you press the Shutter button. Use this mode when long exposures are required, such as for pictures of night scenes and fireworks displays.
Film Speed, ASA and ISO Settings
The ASA rating and its modern equivalent, the International Standards Organizations ISO number, began as rating of film speed. Film speed/ISO is the relative sensitivity of film to light. "Faster" films, those with higher ASA/ISO ratings, have greater light sensitivity than "slower" films. While ISO 400 film is a reliable, general-purpose choice, films with an ISO rating of 3200 or 1600 are a better choice for shooting under subdued light; ISO 60 or 100 films would be appropriate for outdoors use on bright, sunny days. Higher speeds/ISOs may result in lower-quality images than lower speeds. (You may notice grain or snow in the image.) Therefore, you may want to use a flash and a lower ISO setting. In digital photography, ISO numbers are used to adjust the light-sensitivity of the cameras charge-coupled device (CDD), a computer chip that electronically converts light into a digital image.
The 35mm SLR camera has an ASA/ISO setting control (usually a small ring located around the shutter speed dial as in Figure 1-1). Normally, you should adjust the setting to match the ASA/ISO of the film you will use. For a digital camera, set the ISO in accordance with the manufacturers recommendations for the lighting conditions. Generally, when selecting an exposure setting, begin with lower exposure index settings; reserve the use of higher speeds for situations requiring their use.
Digital camera users will also select the file format (TIFFs or JPEGs) in which the image will be recorded. (JPEG is the most common format for still images.)
The term "exposure" is used with a variety of meanings at different times. Photographers often use the term "exposure" to indicate combinations of shutter speed and lens aperture (f/stops). This is properly called "camera exposure."
Various combinations of f/stops and shutter speeds can give the same camera exposure. This is called "equivalent exposure." Example: A starting exposure combination of 1/250 second at f/4 can be changed to an equivalent exposure of 1/30 at f/11 (see Figure 1-3). This can then be changed to an equivalent exposure of 1/125 at f/5.6. Each time you increase the shutter speed by one setting (allowing less light in) you must open up the aperture by one stop.
Figure 1-3. Equivalent exposure.
Again, various combinations of lens aperture and shutter speed can give the same camera exposure. The key is that these combinations allow the same total amount of light to pass through the lens, and onto the film. Any given subject will reflect a variety of light. By this we mean various object brightness will reflect varying amounts of light. Without these various reflectances, we would not have an image on the film. All we would have is an even tone or shade of gray. Thus, the camera settings must be adjusted so as to produce the correct range of camera exposure on the film for your particular subject (Figure 1-4).
Figure 1-4. Exposure
Another meaning of "exposure" is "film exposure." This refers to how the film has been exposed. Did it come out too light or too dark? There are four variable, and interrelating, factors in getting the correct film exposure:
Modern 35mm single-lens reflex and digital cameras have built-in exposure meters. Before the exposure meter can give out accurate information, it must be programmed by "dialing in" the ASA/ISO of the specific film being used. This is usually done with a small ring (the ASA/ISO setting) located around the shutter speed dial or by adjusting a knob or switch. You are not "changing" the ASA/ISO of the film. You are telling the exposure meter what the ASA/ISO of the film is or in the case of a digital camera, adjusting the sensitivity of the CCD.
The objective of photography is to capture not only form but the true colors, shades and hues of that form. Because the cameras ability to capture these are influenced by extremes of lighting conditions (indoor fluorescent or tungsten lighting, versus outdoor sunlight, etc.), appropriate camera settings and film or combinations of film and flash must be used. In digital photography, "white balance" adjustment compensates for these lighting extremes. The digital photographer focuses on a nearby white object to calibrate the camera.
Design: David L. Heiserman
Publisher: SweetHaven Publishing Services
Copyright © 2007, SweetHaven Publishing Services