PHOTOGRAPHY -serious talk:
PHOTOGRAPHY -serious talk:
table
| introduction | history | film | lighting | lenses |
| aperture | f stops | filters | exposure | adjustable |
| composition | focus | color | shutter speed | camera types |
| depth of field | meters | |||
Photography - the process of making pictures by the action of light. Light, reflected from objects, forms a picture on material sensitive to light (the film, which produces negatives). This picture on the film is chemically processed into a photograph. The word photography comes from Greek words meaning to write or draw with light.
The process to make a photograph begins, and ends, with light. Rays of light enter a camera and are focused to form an image. The light makes changes on the film's surface. Exposed film is treated with chemicals (developing), and light is again used to make a print by transferring the image from the film to a sheet of special paper.
There are five principal steps to photography: (1) capturing light rays, (2) focusing the image, (3) exposing the film, (4) developing the film, and (5) making a print. Anyone can take a photograph, using a camera, film, light, and a subject. First, look through the viewfinder to see what will appear in your picture. Next, press the shutter release button to let light from the subject enter the camera and expose the film. After advancing the film, repeat the process for the next picture until all of the film is used.
To take a truly good photograph, you must follow certain principles of photography. Try to "see" as the camera does--that is, be aware of the elements that compose a picture. Also, know the effects of different types of light on film. For cameras with controls to adjust the focus and the amount of incoming light, know how the lens works and how exposure can be controlled. These aspects of good photography can be grouped as (1) composition, (2) light, (3) focusing, and (4) exposure.
Composition (the arrangement of elements in a photograph), includes line, shape, space, and tone or color. Composition is basically a matter of individual taste. However, some guidelines for using various elements of composition may help you create a more desirable photograph.
Both real lines and implied lines can direct a viewer's eye to various parts of a picture. In the most effective photographs, these lines draw attention to the main subject. The direction of these lines can also be used to reinforce the mood of a picture. Vertical lines (those of a tower or a tall tree) may convey a sense of dignity or grandeur. Horizontal lines tend to suggest peace and stillness, and diagonal ones may emphasize energy and tension. [click here to return to the table ]
There are two basic types: natural light and artificial light. Natural light is normally present in outdoor locations. Light has certain characteristics that affect the quality of photographs. These characteristics include (1) intensity, (2) color, and (3) direction.
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Lighting affects the degree of contrast in a photograph. A high lighting ratio usually produces sharp images with strongly contrasting light and dark tones. A low ratio creates softer images with a wide range of medium tones. Therefore, a high lighting ratio can increase the sense of drama and tension in a picture, while a low ratio makes portraits and still-life photographs look more natural (best tool in black and white photography).
Front lighting comes from a source near or behind the camera, showing surface details clearly (not good for pictures of people, because light makes them squint and it casts harsh shadows under their features).
Back lighting comes from a source behind the subject. Light from this direction casts a shadow across the front of the subject. Light from a flashbulb or electronic flash can be used to fill in such shadows. If back lighting is extremely bright, the picture may show only the outline of the subject, which is a good way to create silhouettes. [click here to return to the table ]
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In nonadjustable cameras, focus depends on taking pictures a certain distance from the subject, usually 6 feet (1.8 meters) away. If the subject is closer, the picture will be blurry.
Adjustable cameras have a focusing mechanism that
changes the distance between the lens and the film, with some
manner of indicating when the image has been focused.
[see more adjustable info below]
In nearly all cameras, the aperture is part of a lens system. The lens system concentrates incoming rays of light on the film. The lens gathers enough light to expose the film in a fraction of a second. Without a lens, the exposure might have to last as long as several minutes or even hours.
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Exposure affects the quality of a photograph more than any other factor. Too much light overexposes the film, and the picture will be too bright. With insufficient light, film gets underexposed, resulting in an obscured dark picture.
In nonadjustable cameras, exposure is set automatically. Most adjustable cameras have controls that regulate incoming light.
Controlling exposure. Adjustable cameras have two controls to regulate exposure. One changes the speed of the shutter, and the other changes the size of the aperture.
[f-stops] Shutter speed measures time the shutter remains open to let light expose the film. A slow shutter speed lets in more light, and a fast shutter speed admits less. Various shutter speeds may range from 30 seconds to 1/8,000 of a second (represented by whole numbers on the standard scale of shutter speeds). The number 500 on the scale stands for 1/500 of a second, 250 means 1/250 of a second, etc. Each number on the scale represents twice the speed of the preceding number or half the speed of the next number. At a setting of 250, for example, the shutter works twice as fast as at a setting of 125 and half as fast as at a setting of 500.
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Fast shutter speeds allow sharp pictures of moving subjects.
Any movement of the subject will be recorded as a blur while
the shutter remains open. At a setting of 1/1,000 of a second
or faster, the shutter is open for such a short time that even the
motion of a speeding race car appears to be "stopped." Most
ordinary movement can be stopped at shutter-speed settings of
1/60 or 1/125.
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Aperture size is changed by a device which consists of a circle of overlapping metal leaves. This diaphragm expands to make the aperture larger and contracts to make it smaller. A large aperture admits more light than a small one. The various sizes of an aperture are called f-stops or f-numbers. On most adjustable cameras, the f-stops range from 1.4 or 1.8 to 22 or 32 and include 2, 2.8, 4, 5.6, 8, 11, and 16. The smaller the number, the larger the size of the aperture. Like the shutter speeds, each f-stop lets in either twice as much light as the preceding setting or half as much light as the next higher setting. For example, if you open up the setting from f/11 to f/8, the aperture admits twice as much light into the camera. If you stop down the setting from f/11 to f/16, the aperture lets half as much light into the camera.
Changes in aperture size affect the overall sharpness of the picture. As the aperture becomes smaller, the area of sharpness in front of and behind the subject becomes larger. This area of sharpness is called depth of field. It extends from the nearest part of the subject area in focus to the farthest part in focus. A small aperture, such as f/11 or f/16, creates great depth of field. As you open up the aperture, the area in focus becomes shallower. At f/4 or f/2, the subject will be in focus, but objects in the foreground and background may be blurred.
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Setting the exposure. The proper exposure for a picture
depends chiefly on (1) lighting, (2) subject, and (3) desired
depth of field. Choose a combination of settings that will meet
all your requirements.
On a cloudy day, reduce the shutter speed and increase the f-stop. On a sunny day, use settings for a fast shutter and a small aperture. Certain types of artificial lighting have special requirements for exposure. You may have to experiment with different settings.
For example: Suppose you want to photograph some squirrels on a sunny day. A suitable exposure for this type of lighting might be a shutter speed of 1/60 and an aperture of f/11. If the squirrels are moving, you might decide to increase the shutter speed to 1/125. This speed is twice as fast as 1/60, and so half as much light will reach the film. You should make the aperture twice as large by setting it at f/8. In the same way, if you change the shutter speed to 1/250--four times as fast--you should change the f-stop to f/5.6--four times as large.
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There are four main types of photographic equipment: (1) cameras, (2) film, (3) lighting equipment, and (4) filters.
Nearly all cameras have the same basic design, which includes an aperture, a shutter, a viewfinder, and a film advance system. However, cameras vary widely in such features as adjustability (and the type of film to be used). The simplest cameras, called fixed-focus cameras, have a nonadjustable lens and only one or two shutter speeds.
Single-lens reflex cameras enable a photographer to look at a subject directly through the lens. A mirror mechanism between the lens and the film reflects the image onto a viewing screen. When the shutter release button is pressed, the mirror moves out of the way so that light exposes the film. With this camera, you see the image almost exactly as it is recorded on the film, and parallax error is avoided.
Most single-lens reflex cameras (usually heavier and more expensive) use 35-millimeter film. These cameras have a wide variety of interchangeable lenses (including wide-angle, telephoto, macro, and zoom lenses).
Lenses A macro lens is used in close-up photography. A zoom lens combines many features of standard, wide-angle, and telephoto lenses.
Twin-lens reflex cameras have their viewing lens directly above the picture-taking lens. The image in the viewing lens is reflected onto a screen at the top of the camera. A person holds the camera at waist- or chest-level and looks down at the viewing screen.
A twin-lens reflex camera has some advantages: (1) The viewing screen is much larger and clearer than those of eye-level cameras. (2) Most twin-lens reflex models use film that produces negatives measuring 21/4 by 21/4 inches (5.7 by 5.7 centimeters). The disadvantages, however, are that these cameras are subject to parallax error and are heavier than the majority of single-lens reflex cameras. Also, most twin-lens reflex cameras do not have interchangeable lenses.
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Film varies in a number of characteristics that affect the overall
quality of photographs. The most important of these
characteristics include (1) speed, (2) graininess, (3) color
sensitivity, and (4) color balance.
Speed is the amount of time required for film to react to light. The speed of a film determines how much exposure is needed to record an image of the subject. A fast film reacts quickly to light and needs little exposure (useful for scenes that have dim light or involve fast action). A medium-speed film requires moderate exposure and is suitable for average conditions of light and movement. A slow film needs much exposure and should be used for stationary subjects in a brightly lighted scene.
The higher the ASA or ISO number, the faster the film. Films that have numbers of 200 or higher are generally considered fast. Medium-speed films have numbers ranging from 80 to 125, and slow films are numbered lower than 80.
Graininess is the speckled or hazy appearance of some photographs. The degree of graininess depends on the speed of the film. The fastest films produce the grainiest pictures. Medium-speed films and slow films produce little or no graininess in standard-sized prints, though some graininess may appear for their enlargements.
Color balance applies only to color film. Such film is sensitive to all colors, including those of different kinds of light. Color film records light from light bulbs as reddish, light from fluorescent bulbs as blue-green, and daylight as slightly blue.
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Exposure meters, also called light meters, help
determine the correct exposure. Exposure meters are held in the
hand or are built into a camera. Handheld meters record the light
in a scene and indicate the camera settings for the proper
exposure. Built-in meters measure the light that strikes the lens of
the camera (readings appear on a scale on the viewing screen).
Some cameras with exposure meters automatically adjust the
shutter speed and aperture size to the amount of light available.
Exposure meters are classified according to the way they
measure light.
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Artificial lighting devices. The most widely used sources of
artificial lighting are (1) flashbulbs and (2) electronic flash. Most
cameras have a built-in device called a flash synchronizer. A
flash synchronizer coordinates the flash system with the shutter,
so that the greatest brightness of the flash occurs at the instant
the shutter reaches its full opening.
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In fixed-focus cameras, flash pictures will be correctly exposed if taken at a certain distance from the subject. This distance is listed in the camera's manual. In adjustable cameras, the flash exposure is controlled by changing the size of the aperture. To determine the proper f-stop, find the guide number in the instructions that come with the flashbulbs. Then divide this guide number by the number of feet between the flashbulb and the subject. For example, if the guide number is 80 and the distance is 10 feet, the correct f-stop would be f/8.
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A photographic filter is a disk of colored, plastic-like
gelatin or colored glass in a holder. The holder fits over the
lens of a cameras. Filters screen out haze and glare or increase
the contrast among tones in a picture. Nearly all filters hold
back some light from the film. Therefore, when using a filter
(on most cameras), you should increase the exposure by the filter
factor listed in the instructions provided with the film.
The most widely used filters include ultraviolet, polarizing, and color filters. An ultraviolet filter reduces haze. It is useful for photographing distant subjects and for taking pictures at high altitudes. A polarizing filter screens out glare from shiny surfaces, such as water and glass. A color filter increases contrast in black-and-white photographs. It lets light of its own color pass through the lens to the film but holds back certain other colors. As a result, objects that are the same color as the filter appear light in the picture, and the blocked colors are dark. For example, if you use a red filter when taking a black-and-white photograph of an apple tree. The apples will look light gray, and the leaves and the sky will be dark gray or black.
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A crude type of camera was developed by around 1500. However, the first true photograph was not made until 1826. Early photographers needed expensive equipment and a knowledge of chemistry. Gradually, because of scientific and technical discoveries, cameras became more efficient, less expensive, and easier to operate, making photography available for everyone.
Early developments. The ancient Greek philosopher Aristotle observed that light passing through a small hole in the wall of a room formed an upside-down image of an object. The first crude camera, called a camera obscura (dark chamber), consisted of a huge box with a tiny opening in one side that admitted light. On the opposite side of the box, the light formed an inverted image of the scene outside. The camera obscura was large enough for a person to enter, and it was used chiefly by artists as a sketching aid. They traced the outline of the image formed inside the box and then colored the picture.
A camera obscura could only project images onto a screen or a piece of paper. Scientists sought a way to make the images permanent. Cameras and film were perfected, and by the late 1870's, improvements had reduced exposure time to 1/25 of a second or even less. Photographers could now take pictures while holding the camera in their hands.
In 1888, George Eastman introduced the Kodak box camera. The Kodak was the first camera designed specifically for mass production and amateur use. It was lightweight, inexpensive, and easy to operate.
Besides being important for recording events and people, the importance of taking pictures was realized when photographs of the Yellowstone area helped persuade Congress to establish the world's first national park there [three cheers!!!].
Some photographers concentrate on ordinary subjects or natural
scenery. Many pictures emphasize the textures and geometric
shapes of everyday objects. Others specialize in landscapes,
especially the mountains and deserts of the West.
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