| SECTION 1 | SECTION 2 | SECTION 3 | SECTION 4 |
PHOTOGRAPHY AND THE TEACHER
A TEACHER'S MANUAL
Prof. Carl Edwin Lindgren, D.Ed.
Recently, the author had the opportunity of meeting a young lady who had just entered the mysterious world of photography. In the past, much of her studies were related to the concept of pure art forms. As an artist, however, she had learned many techniques which made her photographic work, even at its early stages, quite outstanding. Given the necessary time, she could prove to be a true Master.
Photography must depend upon the artistic creations of the photographer and the technical and analytical concepts of pure science. Blended together, these two distinct concepts mold the photographic process. A photographic course, whether taught by a elementary or secondary teacher, should endeavor to provide the student with an understanding of the close relationship between these concepts.
Due to its blending of science and art, photography can be integrated into most school curriculum. In the following chapters, information will be provided concerning: introductory photography, darkroom techniques, and the integration of photography with other disciplines.
This manual is to be used as a reference or "starting point" for teachers interested in photography. Through a combination of other texts, teacher determination and curiosity, and student motivation, the manual will provide many hours of beneficial activities.
February 1998
TABLE OF CONTENTS
PART 1
I. INTRODUCTION TO PHOTOGRAPHY
Objectives
Suggested Materials.
Heading Outline and Time Schedule
Activities
Group Enrichment Activity 1
Group Enrichment Activity 2
Group Enrichment Activity 3
The Camera.
Types of Cameras
Dynamic vs. Static
The Lens
Controlling the Depth of Field
The Shutter.
Taking the Picture
The Rules of Composition
Film, Lighting, and Filters.
Film
Lighting
Filters
WORKS CITED
II. SAFETY IN THE DARKROOM
Objectives
Suggested Materials
Sub-heading Outline and Time Schedule
Activities
Group Enrichment Activity
Darkroom Safety
Knowing Your Chemicals
Symptoms
Personal Safety
Fingers vs. Gloves
Ventilation
The Clean-up
Summary
Notes
WORKS CITED
III. THE DARKROOM AND ITS EQUIPMENT
Objectives
Suggested Materials
Sub-heading Outline and Time Schedule
Activities
The Darkroom Experience..
The Film.
The Darkroom
The Necessities
Making the Developer
The Enlarger
The Lens
The Negative Carrier
The Other Features
Notes
WORKS CITED.
IV. DEVELOPING YOUR FIRST ROLL OF FILM
Objectives.
Suggested Materials
Sub-heading Outline and Time Schedule.
Activities
Group Enrichment Activity
Developing Your First Roll of Film
The Equipment
Preparing the Solutions
Opening the Film
Rules to Remember
Notes
WORKS CITED
V. THE FINAL PROCESS: ENLARGING, PRINTING, MATTING AND FRAMING.
Objectives.
Suggested Materials
Sub-heading Outline and Time Schedule
Activities
Group Enrichment Activity
Printing & Enlarging and the Finished Product
The Paper.
Brands
Surfaces
Speed
Contrast
RC vs. Fiber Paper
The Chemicals
The Stop
The Fixer
The Safelight
The Contact Sheet
Procedure.
Test Strips & the Electronic Measuring Device
Test Strip
The Exposure Meter
The Enlargement
Mounting the Print
Dry Mounting
Self-adhesive Tissue
Matting
Framing the Print
WORKS CITED
VI. TEACHING PHOTOGRAPHIC HISTORY
Objectives
Suggested Materials
Heading Outline and Time Schedule
Activities
Group Enrichment Activity
Additional Enrichment Projects
A Short History of Photography
The Search
The Camera Obscura
The Camera Lucida
Drawing with Light
The Discovery.
Niepce's Experiments
Daguerre and Niepce Meet
Further Discoveries
William Talbot
The Talbot -- Reade Dispute
Talbot's Achievements
Ponton and Poitevin
The Traveling Camera
Wet-Plate Photography
The Year Photography Became an Art
The Painting vs. the Print
The Technique
Scenes of the Art Photographer.
Contributions of Pictorialism to Photography
Photography in the 20th Century.
Documentary and the Photographer
Society and Photography.
The 1950s to the Present.
Electronic Photography.
WORKS CITED
VII. PHOTOGRAPHY IN THE SOCIAL STUDIES CLASS.
Objectives
Suggested Materials.
Heading Outline and Time Schedule.
Activities
Group Enrichment Activity 1
Group Enrichment Activity 2
Group Enrichment Activity 3
A Photographic Study of Local Culture
The Scenic View
Photographing the Locale.
Photography and Sociology.
A Discovery
The Indian Technique.
The Painted Photograph.
Indian Reality vs. Western Reality
Conclusion
WORKS CITED
VIII. PHOTOGRAPHY IN THE SCIENCE CLASS.
Objectives
Suggested Materials
Sub-heading Outline and Time Schedule
Activities
Science and Photography
Photographing the Stars
Photomicrography.
Dark Field vs. Bright Field.
Calculations
Films
Geology,
Fossils, and the Camera
Biology and Photography Outdoor Nature Photography Plants and Flowers Large and Small Animal Photography Nature and Infra-red Photography
WORKS CITED
IX. A FURTHER LOOK AT PHOTOGRAPHY IN THE CLASSROOM.
Objectives.
Suggested Materials.
Sub-heading Outline and Time Schedule
Activities in English
Activities in Sports and Physical Education
Activities Relating to Careers and Hobbies
Group Enrichment Activity 1
Group Enrichment Activity 2
Techniques for Integrating Photography
English, Literature and Writing
Journalism and the Camera
Photojournalism Tips
Sports and Physical Education
The Film and Shutter
Pre-focusing
Zooming In
Conclusion
Careers
Photojournalism
Freelancing
Your Own Business
Conclusion
WORKS CITED
CHAPTER 1
learn how to operate a 35 mm camera and demonstrate these techniques;
identify and use the rules of composition;
identify and describe the major camera types;
identify and use the major types of lens (wide angle, zoom, tele-photo and normal); and
use various filters and lighting.
|
exposure meter |
film |
camera |
studio lighting |
|
filters |
flash |
videos |
charts |
|
close-up lens |
a release bulb |
bean bag |
overhead projector |
|
examples of graininess |
change bag |
connectors & cable release |
transparencies |
Heading Outline and Time Schedule
WEEK 2 - Taking the Picture
WEEK 3 - Film, Lighting, and Filters
1. practice focusing, composition and aiming (with an unloaded camera);
2. take a series of pictures using different filters, lenses, and lighting conditions;
3. take a roll of film (12 prints) identifying the major rules of composition (e.g., balance, center of interest, parallel lines, framing, etc.);
4. take pictures using different speeds of film and compare grain, contrast, and clarity;
5. visit a photographic studio and see the professionals at work;
6. visit a photographic exhibition;
7. using different shutter speeds and f/stops, compare the results;
8. taking the same picture several times bracketing the f/stop (ex., f/16, F/11, F/64, compare the differences;
9. take a series of pictures using panning [Panning was not discussed in this chapter so you would have the opportunity of having students research this interesting technique];
10. take a landscape picture using black & white film [Be sure to include a segment of sky. Retake the same shot using a 25 red filter. Compare the prints. Are they different?];
11. photograph a store display (through glass display window) using a 50mm lens [Then have them take the same picture using a polarizing filter. Do the two photographs differ? Is there the same amount of reflection in both pictures?];
12. have students use the filter to darken sky scenes;
13. buy two rolls of color film [The first roll should be ASA 100 and the second ASA 1000 or above. Take similar photographs. Compare the prints as 3 2 x 5, 5 x 7, and 8 x 10. Is grain evident in the prints make with the higher ASA films?];
14. make several pictures, both indoor and outside, which produces a silhouette effect;
15. produce a series of pictures using natural and flash lighting; and
16. take six pictures, using a light meter for both indoor and outdoor photography.
The student will be able to list and describe the major parts of their camera and how these parts, working together, produce a picture.
Through a series of short lectures, video-tapes, readings and discussions, students are introduced to the parts of a camera. Pupils working in small groups, are asked to present a transparency of a camera and describe its workings before the class. A second group, hypothesizes how cameras of the future may be built and used. This activity may be oral or written.
The
student will gain a working knowledge of how to use a 35mm camera (e.g. depth of field, focus,
f/stops, shutter
speed, etc.)
Purpose
To learn how to operate a 35 mm camera and demonstrate these techniques. To obtain an awareness of their community. To create works of photographic and historical significance. To display their works at their local school.
In
this activity, the students are taught how to aim the camera, focus correctly,
use depth of field, f/stop, shutter speeds and all other mechanics necessary in
correct picture taking. Initial activities consist a series of steps including:
lectures, videotapes, hands‑on experience and selected readings. This activity consists of going into the
community, singularly or as a group of three, and taking a series of 12
photographs of old abandoned buildings. The film is then developed and printed
into 5x7 format (by a professional lab. or corner drug store). Students are
then requested to contact older citizens in the community to determine what the
buildings were used for in previous times. The information and photos are
combined into a display which is presented in the form of a mini photographic
essay.
Group Enrichment Activity 3
Purpose
To define, verify, and use applications relating to the rules of photographic composition. To recognize visual perception as it relates to individual photographs. To recognize and implement photographic skills, pertaining to composition, in the taking of personal 35mm pictures.
Previous Activities
Students introduced to camera use.
Current Activity
Initially,
students receive video instruction and short lecture and question sessions
relating to composition. In this activity, students are to photograph everyday
items within the community from a new and unusual perspective. These
photographs, when developed and printed, are combined with text to describe the
items new perspective (using lines, framing, center of interest, rule of
thirds, etc.) and then bound to form a small booklet which will be distributed
to elementary students.
The Camera
The camera is, indeed, the most important piece of equipment that a photographer can have. Quite frankly, without the camera no picture can be taken. A camera, however, is not always what we perceive it to be. According to The American Heritage Dictionary (1989) a camera is, "an apparatus consisting of a lightproof enclosure having an aperture with a shuttered lens through which the image of an object is focused and recorded on a photosensitive film or plate" (p. 100).
Never be intimidated by the more expensive camera or lens. Good 35 mm cameras (Single lens reflex - SLR) can be purchased for about $200.00. According to Feininger (1982):
All 35 mm cameras costing 175 dollars and up are capable of yielding negatives and transparencies of satisfactory technical quality. Furthermore, I am convinced that a photographer who cannot produce effective pictures with a hundred‑dollar camera would do no better with a fifteen hundred‑dollar model. It is not the technical quality of his camera which decides the value of his pictures, but whether or not it is suited to the job at hand. (p. 23)
There are many types of cameras but perhaps the best known are:
1. the 35 mm (SLR or viewfinder);
2. the medium format - 2 1/4 x 2 1/4 and 2 1/4 x 2 3/4-inch single-lens reflex (SLR) and twin-lens reflex (TLR,) and 4" x 5";
3. the large format or field camera.
Any
time a photographer is interested in dynamic subjects whether they be sporting
events, wildlife, people or pets, the 35 mm format is by far the best. Because
of its small size and light weight, the 35mm can be carried just about
anywhere. From the model F Nikon, built in 1959 (Snyder, 1976), to the ultra-modern,
totally electronic Minolta or
The following formula (Benedict, 1976), known as the Basic Exposure Formula, explains the use of ASA or ISO
| + 1 Haze | + 2 Light cloudy day | + 3 Dull Cloudy |
In this equation, an ASA of 400 (Tri-X film relatively high grain film) would have a shutter speed of 500 at an aperture of f/16. The same would apply with an ASA of 100 with a shutter of 125 at f/16. On page 25 of Benedict's book (1976) is an extensive chart of equations relating to these situations.
In
discussing the 35 mm format, a little should be said about the difference
between the single lens reflex and the viewfinder camera. Single lens refers to
a camera where all focusing, exposing and viewing takes place through the lens,
as opposed to the viewfinder model which consists of a frame finder used to view and compose (Carver
& Lee, 1985). Henry Horenstein (1974), in his book, Black and White - A
Basic Manual describes in exacting detail the difference between the
rangefinder (viewfinder) and the SLR. According to Horenstein (1974),
"[t]he choice between a rangefinder and an SLR is a major decision in
buying a camera. Most range-finders are somewhat simpler and less expensive
than SLRs. For occasional use, they are quite adequate. For more extensive use,
they are sometimes inadequate" (p. 147). An exception to this rule would,
of course, be the professional Leica which is extremely sophisticated. Other
differences include (Horenstein, 1974):
|
RANGEFINDER |
Advantages |
Disadvantages |
|
|
simpler |
lacks versatility |
|
|
quieter |
fewer changeable lens |
|
|
cheaper (usually) |
bad close-ups |
|
SINGLE LENS REFLEX |
Advantages |
Disadvantages |
|
|
versatile |
loud |
|
|
more durable |
more expensive |
|
|
excellent close-ups |
heavier |
Known as static subject photography, (Feininger, 1982) this form of subject representation permits the photographer to perform precise calculations. One of the advantages of static subjects is that the photographer can use a tripod to maximize sharpness. When shooting fast moving objects, the photographer must either increase the shutter speed (shutter controls the duration of the exposure) or open the diaphragm (a series of overlapping metal leaves that can be adjusted to specific apertures to control the amount of light entering through a lens) (Carver & Lee, 1985). Opening of the diaphragm (aperture) is rated in f/stops. The lower the f/stop (ex., f/2.8), the larger the aperture, the more light entering the camera, the slower the corresponding shutter speed, and the more shallow the depth of field. The larger the f/stop no., (ex., f/16) means the faster the corresponding shutter speed, that less light enters the camera, a smaller aperture opening, and a greater depth of field. The depth of field is that area of acceptable sharpness in front of and behind the subject that is in sharp focus (Carver & Lee, 1985). In taking photographs, you have probably noticed that some areas are in focus while others are not. In order to have the maximum sharpness in all areas of the photograph, the photographer must use a small aperture (a large f/stop--ex., f./16). Static subjects help in accomplishing this by, as previously stated, allowing for the use of a tripod and f/stops of 64 or higher. This is an area for which the medium and large format camera is especially well-suited. The 35mm, as noted above, is meant for the active and dynamic subject. For the teacher, this type of camera offers the best selection of features, including: ease of operation, light weight, size, and is excellent for use with both dynamic and static subjects.
The Lens
In most cases, when purchasing a camera, one just gets the body. This is especially true for the SLRs and the more expensive medium range cameras. Deciding which lenses are needed becomes a difficult and sometimes confusing endeavor. Perhaps the most popular lens for the SLR is the normal lens which is usually about 50 mm (focal length -"the distance from the film to the center of the front of the lens (when focused at infinity)" (Horenstein, 1974). In addition to the normal lens, there are the wide-angle and the telephoto. The wide-angle, the most common being either the 28 mm or 35 mm, is excellent for wide-angle shots (i.e., landscapes). The telephoto lenses are generally the 105mm, 135 mm, and 200 mm. It is also possible to buy 500mm and even 1000 mm. These lenses are, however, extremely expensive and require a large aperture opening (usually an f/8 or below). Besides landscape photographs, the 90-105 mm lens is excellent for portrait photography.
Perhaps one of the best bets in purchasing a lens is to buy a zoom lens. The zoom lens, according to The Basic Book of Photography (Grimm, 1985) is "a lens that can be adjusted to varied focal lengths while keeping the subject in focus" (p. 347). The zoom lens in an excellent accessory and at times a definite necessity. The two most popular zooms are the 35-70 mm and the 70-200 mm. With these two lenses in hand, there are very few pictures which cannot be taken. From wide-angle to normal and telephoto, these two lenses will provide a variety of focal lengths. The 70-200mm is an indispensable attachment at weddings, parties, vacationing, and especially for informal portraits. By setting the lens at 105 mm an excellent normal range close‑up may be taken. By increasing the lens to 200 mm, the pictures take on an interesting air of modeling or sophistication. The 70 mm creates a nice full length shot. It should be noted, that in selecting the zoom over stationary lens (e.g., 35, 50, 105, 200 mm, etc.) one must sacrifice some quality of sharpness. With new technology in lenses, the difference in clarity is not normally perceivable.
In connecting the lens to the camera body, the manufacturers have chosen two approaches. The first, called the screw mount is exactly that - the lens is screwed into the camera body. The second method is called the bayonet mount. In this mount process, the lens is dropped into a slot, usually indicated by a red dot, and turned slightly. The lens then locks into place. Although normally, one mount is a useful as the other. In an emergency, however, time is of the essence. Even the few seconds required to unscrew and screw on lenses may cause the loss of a picture. For this reason, the bayonet method is usually preferred.
The autofocus lens, a relatively new invention, helps the photographer in determining the correct distance for taking a shot by automatically adjusting the lens to the correct focus (Grimm, 1985). This is accomplished by the use of an optical sensor. Autofocus lenses and cameras are becoming abundant and affordable. It is also possible to exchange some autofocus lenses to other autofocus cameras. Until recently, the autofocus produced several unfavorable effects. The most obvious was the tendency of the camera lens to focus on the center of the object. This is undesirable if the photographer is attempting to focus on several items or an item outside the center of sharpness. New advances have nearly eliminated this problem.
Another lens which should be discussed is the close-up lens. The close-up lens has the ability to focus on extremely close objects, making it possible to take pictures of flowers, insects, etc. These lenses attach in front of the normal lens and are usually screwed, by the use of threads, onto the normal, telephoto zoom, or individual close-up lens. Close-up lenses are usually referred to in power or strength sequences. Examples would be: +1, +2, & +4 . . . +10--a plus 10 being the strongest. An increased closeness may be obtained by employing a tube known as an extension tube. According to Grimm (1985), the extension tube is "one or more rigid tubes or rings used for making close-ups; inserted between camera lens and body to increase lens focal length and magnify the subject" (p. 337).
The macro lens is one which is sometimes confused with the close-up lens. The macro lens refers to the lens itself without the use of any extension (ex., close-up attachment or extension tube). This means that the macro lens looks similar to the normal, zoom, or wide-angle variety except that the lens is designed specifically to focus on extremely close objects. The macro lens, although more expensive than the close-up attachments, allows the photographer to take sharper, easier close‑up shots. Some lenses allow the photographer to focus as close as 2 inches in contrast to normal lenses which allow a close focus at no less than 1.5 feet.
Another consideration in selecting lenses
is their price. Lenses, like everything else, vary greatly in cost. Some are available for less than $100.00,
while others prices soar into the thousands. Although lenses are manufactured
throughout the world, the best are produced in
Aside from light, one of the most important aspects of photography is controlling the depth of field. This photographic technique is often times misunderstood or ignored by the novice (in most cases with disastrous consequences). Although previously discussed, this topic deserves some further clarification.
According to Carver & Lee (1985), depth of field is the "range of sharpness, lying about one third in front of the focus point and two thirds behind . . ." (p. 17). In some cases, it is desirable to have all areas of the photograph in focus. At other times, however, the photographer may wish to have certain areas of the print in focus while others are deliberately out of focus (Feininger, 1982). According to Horenstein (1974) there are three ways of controlling the depth of field. The first and most important control is aperture. By opening and closing the aperture (or increasing or decreasing the f/stop), a photographer can determine the depth of the shot. A large aperture (ex., f/2.8) means a small depth of field while a small aperture (ex., f/16) means a large field. The second way to control the field is by varying the distance between the subject and the camera. Quite simply, the greater the subject to camera ratio, the larger the depth of field. The final control is the focal length of the lens. A normal lens (50 mm) will provide greater depth of field than a telephoto lens (200 mm) which produces a shallow depth of field.
In determining the depth of field, the photographer using the SLR is assisted by being allowed to preview the final composition of the shot. "As the aperture gets smaller or larger, the zone of focus visibly increases or decreases" (Horenstein, 1974, p. 28). When using automatic lenses, however, the lens aperture always remains open to its fullest degree. This changes only the second the picture is taken. For this reason, another method must be used for determining or viewing the field. Therefore, many cameras have a manual or preview button on the side of the camera. When using the preview button the operator, while looking through the camera, presses the button (Horenstein, 1974). This steps down the lens to the prescribed f/stop opening. What about the depth of field scale? This scale, is located on the barrel of the lens. Printed on the camera lens are two movable scales. The first is the aperture ring which consists of series of f/stop numbers (ex., f/16 11 8 5.6 4 2.8 1.9). The second is the focusing ring. This ring, by turning to either the left or right, brings the camera lens into focus. This ring consists of a series of numbers known as a distance scale. When a subject stands a certain distance from the camera (e.g., 15 ft.) he will be in focus when the distance scale reads 15 feet. When the individual is in focus, turn the aperture ring to determine the correct f/stop setting. If you select a f/8 or any other f/stop number the depth of field can be determined by looking at the small line of numbers between the aperture and focus ring. These numbers are usually set up as follows:
16
' 8 '' * ' 8 ' 16
ft
30 15 10
7 5 4
3 2.5
By
using the above information of a focus of 15 feet and a f/8, the photographer
can look at the middle non‑movable ring. In this case depth of field would be
between 12 ft and 30 ft.
16'8''*'8'16 depth non-movable ring
16 11 8 5.6 4 2.8 1.9
aperture ring (f/stops)
One more term to remember, circles of confusion. This term refers to the "range of sharpness both in front of and behind the point of focus . . ." (Carver & Lee, 1985, p. 16). Most photographers, both professional and amateur have learned through trial and error, the importance of depth of field. Another area, closely related to depth of field is hyperfocus distance. This technique has been used by photographers for many years to produce outstanding prints. When the photographer focuses his lens on a subject a considerable distance away (ex., infinity), the "depth of field extends from infinity to a point closer to the camera. Depending on the f/stop, the infinity to near focus distance is called hyperfocus distance" (Carver & Lee, 1985, p. 19). Concerning this matter, Carver & Lee (1985) has suggested the following chart:
f/4 f/5.6 f/8 f/11 f/16
70 60 55 45 30
H = ----
the units H being the same as for f. (p. 128)
[An understanding of this matter does] away with the
old-wives-tales about wide angle lenses having enormous depth of field,
especially when the amount of enlargement could be varied. This . . . [directs
the student's attention toward] a discussion of using the lens focal length to
control perspective rather than depth of field when enlargement can be varied.
After a series of pictures with lenses of different focal lengths [it is
concluded] that normal perspective is gained with a 100 mm lens on a 35 mm
camera rather than the 50 mm so-called "normal" lens. (p. 1)
"A device, built in the lens or camera, that regulates the length of time that light reaches the film to make an exposure." This, according to Tom Grimm (1985, p. 344) is the definition for a shutter. Exactly what does this mean? This section will attempt to explain to the teacher or amateur photographer, in simple detail, the meaning, workings, and results of the photographic shutter.
The shutter has two main functions: controlling the timing and controlling the movement (Horenstein, 1974). In controlling the timing, the shutter is used to regulate the amount of light entering the lens of the camera and striking the light sensitive film. The time period during which light enters and strikes the film or the period in which the shutter is open is called the shutter speed. Speeds vary on some cameras from thousandths of a second to the "T" and "B" selections which allow for shutter to be locked into an open position. The "T" position (time) allows the shutter to remain open until the shutter button is repressed. The "B" position (bulb) is open as long as the shutter button, bulb, electronic shutter button, etc. is pressed. Once the button is released, the shutter closes. This may be achieved by either directly pressing the button, and holding it down with your finger, or with an accessory known as a cable release. The cable release is "[a] flexible cable that screws into the shutter release and allows the photographer to trip the shutter without pressing the release with his finger; used for time exposures to prevent camera movement" (Grimm, 1985, p. 333). In many cases the release is made of metal and consists of a stiff piece of thin metal which is affixed within a larger piece of hollow tubing. The hollow tubing is screwed into the shutter release on one end and has a metal plunger attachment on the other. When the metal plunger is pressed in, it inserts the thin flexible metal rod into a specially made hole in the shutter release button, thus pressing the button down. The bulb release, similar to the metal cable release, is a plastic or rubber cable which on one end attaches to the shutter button and on the other to a rubber bulb. When the bulb is squeezed, air is forced down the cable and presses the shutter button. As long as the bulb is squeezed, the shutter remains open.
In controlling the movement the shutter, if appropriate to the composition, is used to freeze movement. The faster an object or person moves, the higher shutter speed a photographer must use. If an object is at rest, a shutter speed of 1/30 of a second may be sufficient to provide no blurring. In fact in some cases the shutter may, as previously discussed, be allowed to remain open for seconds or even minutes. If, however, an object is in motion the shutter speed must be set to freeze the movement or action. A person walking may require a 1/250, while a speed boat may require a shutter speed of 1/1000th of a second. Another item to take under consideration when taking a picture is the steadiness of hand of the photographer. If the photographer moves his camera, even very slightly, there is always the possibility that the picture will be blurred. To prevent this from occurring a photographer should always, when hand holding a camera, use a shutter speed of 1/60 or higher (Eastman, 1981). If a speed lower than this is required, it's always best to use either a tripod or monopod. In a "pinch" a bean bag may be used to steady a camera. In this procedure, a camera is placed on the bag and the shutter released either by an air or cable release.