Chapter 7 Close-up Photography and Photomacrography

Transcription

1 Chapter 7 Close-up Photography and Photomacrography Objectives Information in this chapter will enable you to: Discuss the differences between closeup photography, photomacrography, and photomicrography. Discuss the reason why the terms above are vastly different from macrophotography and microphotography. List and describe six different systems of close-up photography and photomacrography. Technical Terms bellows close-up lenses close-up photography extension tube macrophotography microphotography photomacrography photomicrography ring fl ash There are situations where an image is made of a very small object, insect, or flower for the purpose of enlarging the image. You may need to illustrate the raised lettering of a coin or show the beautiful colors of the inside of a flower or capture the texture of the eyes of an insect. See Figure 7-1. All of these tasks depend on your ability to photograph the subject in such a way that, when the image is enlarged, all of the important details are clear. 125

2 126 Exploring Photography 127 Figure 7-3. A 1 (25 mm) subject that fi lls a 35 mm sensor vertically has an image to subject ratio of 1:1. Figure 7-5. This photomural is an example of macrophotography. Figure 7-1. These examples of close-up and photomacrography photos are images that you can create. Imagine a full-frame sensor in a camera. It is about 1 (25 mm) high. An object 3 (75 mm) high filling this frame is reproduced as 1/3 life size. This example has an image to subject ratio of 1:3. See Figure 7-2. A 1 (25 mm) high object filling the sensor has a 1:1 ratio that is life-size. See Figure 7-3. A 1/2 (13 mm) high subject filling the sensor must be enlarged. It has a ratio of 2:1 or a magnification of 2X. The symbol X indicates magnification or times. See Figure 7-4. Magnification Terms The term close-up photography is generally understood to cover the range of 1:10 through 1:1 (1/10 size to life-size). Photographing objects larger than life-size through 25:1 (25X) is called photomacrography. The terms macrophotography and macrography Figure 7-2. A 3 (75 mm) subject that fi lls a 35 mm sensor vertically has an image to subject ratio of 1:3. Figure 7-4. A 1/2 (13 mm) subject that fi lls a 35 mm sensor vertically has an image to subject ratio of 2:1 (2X). are often used incorrectly in place of photomacrography. Macrophotography is the process of creating a photograph that is larger than typical, such as photomurals and billboards. See Figure 7-5. The technique of mounting a camera on a microscope to increase magnification is called photomicrography. See Figure 7-6. Magnifications of 40X with a standard microscope to 500,000X and higher with a scanning electron microscope is possible. See Figure 7-7. The coverage of photomicrography will be minimal due to the limited access most schools have to this type of equipment. The terms microphotography and micrography are often used incorrectly in place of photomicrography. Figure 7-6. Photomicrography, mounting a camera to a microscope, provides the opportunity to photograph the smallest of subjects.

3 128 Exploring Photography 129 Figure 7-7. This photomicrograph of pollen grains was taken on a scanning electron microscope. Microphotography is the process of creating a photograph that is small enough to require a magnifying lens to view the image. Microphotography was used in devices called stanhopes from the 1860s to today. See the History Brief for more information. The terms in the previous paragraphs are very similar with very different meanings. To avoid using these terms incorrectly, study the chart in Figure 7-8. History Brief Stanhope Photos Stanhopes are small cylindrical lenses with a microphotograph attached. The microphotograph is typically 2 2 mm. These lenses were mounted in knives, jewelry, pens, and tobacco pipes. The following describes the time, people, and events related to this curious novelty. 1780s Charles Stanhope invents cylindrical lens John Benjamin Dancer invents microphotographs René Prudent Patrice Dagron combines the lens and the microphotograph to produce novelties called stanhopes. section, research the various ways to gain access to the equipment. Your lenses may be applicable as designed, or you may be able to use these lenses in a nonstandard way to get the intended image. Check the equipment in your school, including the science department you may be able to use one of the microscopes. Consider renting lenses for a project. This is a great way to get experience with expensive equipment that you will not use that often. Close-up lenses are positive supplementary lenses that shorten the focal length. A supplementary lens is an extra or add-on lens. See Chapter 3 for the definition of a positive lens. They are available in different powers. Each is good for a different limited range of closeup distances. The lenses usually come in a set of three, +1, +2, and +4. See Figure 7-9. The higher the number, the greater the magnifying power. They may be stacked to increase magnification. A +1 lens and a +2 lens equals a magnification power of a +3 lens. You should always attach the highest number to the lens first. Stacking reduces sharpness. Close-up lenses are easy to attach. Like filters, they are threaded to fit the front of the regular lens. See Figure Close-up lenses are simple, convenient, inexpensive, and do not require exposure compensation. Reversing Ring A reversing ring, Figure 7-11, is an adapter that permits the lens to be reversed on a camera. It is the least expensive way to practice photomacrography. The reversed lens will give a magnification ratio of 1:1 or life-size with a 50 mm or normal lens. However, the automatic features of the lens are lost. Lens Extension Tubes Closer focusing of a lens is possible by using an extension tube, a device for moving the lens farther from the film plane. Extension tubes, Figure 7-12, are used to extend the lens. This technique has limitations. As the lens extension length grows, the exposure time increases and image sharpness decreases. The way a lens is normally mounted to camera body Equipment and Methods Each stage of magnification requires specific cameras, lenses, and accessories to produce a usable image. While studying this Close-up Lenses Close-up lenses are an inexpensive way to get started in close-up photography. These lenses can be added to almost any camera. Figure 7-9. Close-up lenses are positive supplementary lenses that shorten the focal length of the regular lens. Reversal ring Part of lens that is normally locked to camera body Type of photography Close-up photography Image to subject ratio Subject size Image size Typical subjects 1:1 to 1:10 1 to 5 Any Flowers Photomacrography 40:1 to 1:1.025 to 1 Any Insects, coins Photomicrography Less than 40:1 Less than.025 Any Skin cells Microphotography Any Very small Any Macrophotography Any Very large Any Figure A reversing ring is an adapter that permits the lens to be reversed on the camera for very close focusing. Figure 7-8. Study this chart of the terms used referring to the various levels of magnifi cation in photography so you do not use them incorrectly. Figure Close-up lenses are threaded to attach to the front of the regular lens.

4 130 Exploring Photography 131 Figure Extension tubes are fi tted between the lens and camera body. These tubes can be used individually or in combination. The longer the tube, the closer the lens can be focused on the subject. There are some things to remember when using extension tubes: Longer focal length lenses will give a greater working distance. Wide-angle lenses do not give a greater depth of field than normal lenses when used with extension tubes. A wide angle lens with extension tubes will give a greater magnification of the subject at the cost of more distortion. Magnification ratios must be determined from data charts furnished with the extension tubes. If your camera does not have through-thelens metering, exposure compensation must be calculated. Again, refer to the data charts furnished with the extension tubes. In general, as the lens is moved farther from the film, more light is needed to make the exposure. This requires a larger lens opening or slower shutter speed. Bracketing shots is recommended. Extension tubes give best results when the subject is larger than 1. Bellows A bellows is not a variation of an extension tube. A bellows is a folding cloth sleeve device that provides a lighttight adjustable tube between the lens and camera. See Figure A bellows has a different range of magnification. A bellows is best used when the subject is smaller than 1. They are rather bulky for portable operations and are expensive. Usually, bellows have a scale showing the magnification ratio. As with extension tubes, additional exposure time is required with bellows. Macro and Close-Focus Lenses Macro lenses will focus much closer than regular lenses. In a true sense, a macro lens is capable of providing a 1:1 magnification ratio (life-size image). The term is sometimes incorrectly used to describe a close focus lens. Magnification ratios are usually engraved on the macro lens barrel. See Figure Many will focus to 1/2X or a 1:2 ratio, but may be fitted with an extension ring to allow focusing down to life-size. Still, others will focus to a 1:1 ratio or life-size without any additional accessories. Macro lenses can also be used at normal subject distances. Figure Although more costly and cumbersome, a bellows is more fl exible to use than a close-up lens or an extension tube. (Pentax Corp.) Figure A modern macro lens can be switched between auto focus and manual focus. This lens has a maximum magnifi cation ratio of 1:1. This means a 1 inch high object will appear life-size on 35 mm fi lm which has a frame height of 24 mm or 1 inch. (Tamron) Macro lenses should not be confused with macro zoom lenses. The latter are really close-focus lenses. They do not focus as close as macro lenses and are not optically corrected for flatness. They are fine for taking close-ups of flowers, insects, and the like, but should not be used for flat subjects. Focusing and Framing With a single lens reflex camera, close-up focusing is no different than regular subject focusing. Rangefinder and twin lens reflex cameras present a slight problem. At close distances, the viewfinder does not show exactly what will be photographed. You know this as parallax. Parallax occurs because the viewfinder and taking lens are separated. It can be corrected by slightly tipping the lens toward the viewfinder just before the picture is taken. Many close-up photos are taken outdoors. In such cases, it may be necessary to supplement or modify available light. Using a white cardboard reflector or light tent can eliminate shadows. See Figure A special electronic flash called a ring flash fits on the end of a lens and puts even light all around the subject. See Figure A flash allows the use of a higher shutter speed and smaller aperture. This will provide for a greater depth of field. A distracting background will be very dark. See Figure It may be necessary to experiment to get the best exposure. There are three basic requirements for taking good close-up and macro pictures. If your camera does not have throughthe-lens metering, it will be necessary to compensate for the reduced light reaching the sensor. Keep the camera steady. Use a tripod. Use a small aperture setting for maximum depth of field. White reflector fills in shadows Figure Lighting can be a problem when doing close-up photography. Shadows can often be eliminated by using white cardboard refl ectors or special light tents.

5 132 Exploring Photography 133 Figure A ring fl ash fi ts on the end of a macro lens to provide light close to the subject. (Sigma) Without flash With flash Figure A fl ash allows the use of a high shutter speed and small aperture. This combination provides a greater depth of fi eld and usually darkens a distracting background. Test Your Knowledge Write your answers on a separate sheet of paper. Please do not write in this book. 1. A 3 (75 mm) high subject that fills a full-frame sensor has an image to subject ratio of. 2. A subject having an image to subject ratio of 5:1 has a magnification of. A. 1/5X B..2X C. 5X D. All of the above. E. None of the above. 3. How does photomicrography differ from photomacrography? 4. The optical device that permits close-up photography by shortening the lens focal length is called a. 5. A reversing ring offers the following advantage when making close-up photographs:. 6. The reversing ring, however, has the following disadvantage when making close-up photographs:. 7. A lens is used to extend the lens for closer focusing. 8. Bellows are considered. A. a very complicated way to make close-up photos B. a variable length extension tube C. useless if the subject is less than 1 high D. All of the above. E. None of the above. 9. What problem can be caused by parallax when making close-up photographs? 10. The following are necessary for good close-up and macro photographs:. A. exposure compensation for reduced light if the camera does not have through-thelens metering B. a lens free of fingerprints C. a steady camera D. use of a small aperture for maximum depth of field E. All of the above. F. None of the above.

6 134 Exploring Photography Things to Do 1. Prepare a paper on the industrial or medical uses of photomacrography. 2. Secure samples of photomicrography used in industrial or medical research. 3. Take a series of close-up photos. Submit the photos to your instructor with an evaluation of your work. 4. Demonstrate how close-up lenses are used. Illustrate the demonstration with photos or slides you have taken using the technique. 5. Demonstrate how lens extension tubes are used. Illustrate the problems and limitations of the technique with photos or slides you have taken. 6. Demonstrate how bellows are used. Illustrate the demonstration with photos or slides you have taken using the technique.