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52-566: The technique is based on the late 19th-century sensitometry studies of Hurter and Driffield . The Zone System provides photographers with a systematic method of precisely defining the relationship between the way they visualize the photographic subject and the final results. Although it originated with black-and-white sheet film , the Zone System is also applicable to roll film, both black-and-white and color, negative and reversal , and to digital photography . An expressive image involves

104-403: A Zone V exposure (the meter indication) resulting in a mid-tone rendering in the final image. Each zone differs from the preceding or following zone by a factor of two, so that a Zone I exposure is twice that of Zone 0, and so forth. A one-zone change is equal to one stop, corresponding to standard aperture and shutter controls on a camera. Evaluating a scene is particularly easy with

156-403: A black horse) often will be overexposed. That both scenes require the same exposure, regardless of the meter indication, becomes obvious from a scene that includes both a white horse and a black horse. A photographer usually can recognize the difference between a white horse and a black horse; a meter usually cannot. When metering a white horse, a photographer can apply exposure compensation so that

208-409: A bright light can reflect the same amount of light as a light surface under dim light. The human eye would perceive the two as being very different but a light meter would measure only the amount of light reflected, and its recommended exposure would render either as Zone V. The Zone System provides a straightforward method for rendering these objects as the photographer desires. The key element in

260-400: A chain of events, no less important to the Zone System than exposure and development of the film. With practice, the photographer visualizes the final print before the shutter is released. Unlike sheet film, in which each negative can be individually developed, an entire roll must be given the same development, so that N+ and N− development are normally unavailable. The key element in the scene

312-468: A display setting and possibly a physical dial whereby the photographer can set the camera to either over or under expose the subject by up to three f-stops ( f-numbers ) in 1/3 stop intervals. Each number on the scale (1,2,3) represents one f-stop, decreasing the exposure by one f-stop will halve the amount of light reaching the sensor. The dots in between the numbers represent 1/3 of an f-stop. In photography , some cameras include exposure compensation as

364-510: A feature such as Merge to HDR in Photoshop CS2 and later. A simplified approach has been adopted by Apple Inc. as a selectable HDR option in later versions of the iPhone . The tonal range of the final image depends on the characteristics of the display medium. Monitor contrast can vary significantly, depending on the type ( CRT , LCD , etc.), model, and calibration (or lack thereof). A computer printer 's tonal output depends on

416-484: A feature to allow the user to adjust the automatically calculated exposure. Compensation can be either positive (additional exposure) or negative (reduced exposure), and is frequently available in third- or half-step, less commonly in full steps or even quarter-step increments, usually up to two or three steps in either direction; a few film and some digital cameras allow a greater range of up to four, five or even six steps in both directions. Camera exposure compensation

468-402: A high-contrast scene is given normal development, desired detail may be lost in either shadow or highlight areas, and the result may appear harsh. However, development can be reduced so that a scene element placed on Zone IX is rendered as Zone VIII in the print; this technique is known as contraction , and the development usually referred to as "minus" or "N−". When the resulting change

520-438: A meter that indicates in exposure value (EV), because a change of one EV is equal to a change of one zone. Many small- and medium-format cameras include provision for exposure compensation ; this feature works well with the Zone System, especially if the camera includes spot metering, but obtaining proper results requires careful metering of individual scene elements and making appropriate adjustments. The relationship between

572-412: A scene of 12% reflectance. In a sunlit outdoor scene, the exposure for the dark object would also depend on whether the object was in sunlight or shade. Depending on the scene and the photographer's objective, any of the previous exposures might be acceptable. However, in some situations, the photographer might wish to specifically control the rendering of the dark object; with overall average metering, this

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624-425: A subject of uniform luminance and one that consists of light and dark elements. When exposure is determined from average luminance measurements, the exposure of any given scene element depends on the relationship of its reflectance to the effective average reflectance. For example, a dark object of 4% reflectance would be given a different exposure in a scene of 20% effective average reflectance than it would be given in

676-652: Is a stub . You can help Misplaced Pages by expanding it . Exposure compensation Exposure compensation is a technique for adjusting the exposure indicated by a photographic exposure meter , in consideration of factors that may cause the indicated exposure to result in a less-than-optimal image. Factors considered may include unusual lighting distribution, variations within a camera system, filters, non-standard processing, or intended underexposure or overexposure. Cinematographers may also apply exposure compensation for changes in shutter angle or film speed (as exposure index), among other factors. Many digital cameras have

728-432: Is a ritual if not a form of cult rather than a practical technical procedure. Much of the difficulty may have resulted from Adams's early books, which he wrote without the assistance of a professional editor; he later conceded (Adams 1985, 325) that this was a mistake. Fred Picker (The Zone VI Workshop 1974) provided a concise and simple treatment that helped demystify the process. Adams's later Photography Series published in

780-425: Is a rule of thumb. Some film stocks have steeper curves than others, and the cinematographer needs to know how each one handles all shades of black-to-white. The ISO standard for black-and-white negative film, ISO 6:1993, specifies development criteria that may differ from those used in practical photography (previous standards, such as ANSI PH2.5-1979, also specified chemistry and development technique). Consequently,

832-410: Is commonly stated in terms of EV units; 1 EV is equal to one exposure step (or stop), corresponding to a doubling of exposure. Exposure can be adjusted by changing either the lens aperture or the exposure time; which one is changed usually depends on the camera's exposure mode . If the mode is aperture priority , exposure compensation changes the exposure time; if the mode is shutter priority ,

884-449: Is difficult if not impossible. When it is important to control the rendering of specific scene elements, alternative metering techniques may be required. It is possible to make a meter reading of an individual scene element, but the exposure indicated by the meter will render that element as a medium gray; in the case of a dark object, that result is usually not what is desired. Even when metering individual scene elements, some adjustment of

936-462: Is no claim that the Zone System would be a suitable instrument to comprehend and control the new imaging devices, and Adams explicitly states that electronic systems may have their own characteristics (which might thus require different approaches). Yet another misconception is that the Zone System emphasizes technique at the expense of creativity. Some practitioners have treated the Zone System as if it were an end in itself, but Adams made it clear that

988-473: Is one zone, it is usually called "N − 1" development. It sometimes is possible to make greater adjustments, using "N + 2" or "N − 2" development, and occasionally even beyond. Development has the greatest effect on dense areas of the negative, so that the high values can be adjusted with minimal effect on the low values. The effect of expansion or contraction gradually decreases with tones darker than Zone VIII (or whatever value

1040-484: Is placed on the desired zone, and the rest of the scene falls where it will. Some contrast control is still available with the use of different paper grades. Adams (1981, 93–95) described use of the Zone System with roll film. In most cases, he recommended N − 1 development when a single roll was to be exposed under conditions of varying contrast, so that exposure could be sufficient to give adequate shadow detail but avoid excessive density and grain build-up in

1092-413: Is straightforward: an exposure compensation of one EV is equal to a change of one zone; thus exposure compensation of −1 EV is equivalent to placement on Zone IV, and exposure compensation of +2 EV is equivalent to placement on Zone VII. The Zone System is a very specialized form of exposure compensation, and is used most effectively when metering individual scene elements, such as

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1144-407: Is used for control of high values). Specific times for N+ or N− developments are determined either from systematic tests, or from development tables provided by certain Zone System books. Adams generally used selenium toning when processing prints. Selenium toner acts as a preservative and can alter the color of a print, but Adams used it subtly, primarily because it can add almost a full zone to

1196-510: The Zone System obscures simple densitometry considerations by needlessly introducing its own terminology for otherwise trivial concepts. Noted photographer Andreas Feininger wrote in 1976, I deliberately omitted discussing the so-called Zone System of film exposure determination in this book because in my opinion it makes mountains out of molehills, complicates matters out of all proportions, does not produce any results that cannot be accomplished more easily with methods discussed in this text, and

1248-456: The Zone System practitioner often must determine the speed for a particular combination of film, developer, and enlarger type; the speed determination is commonly based on Zone I. Although the method for determining speed for the Zone System is conceptually similar to the ISO method for determining speed, the Zone System speed is an effective speed rather than an ISO speed. A dark surface under

1300-506: The Zone System was an enabling technique rather than the ultimate objective. Hurter and Driffield Ferdinand Hurter (1844–1898) and Vero Charles Driffield (1848–1915) were nineteenth-century photographic scientists who brought quantitative scientific practice to photography through the methods of sensitometry and densitometry . Among their other innovations was a photographic exposure estimation device known as an actinograph . This photography-related article

1352-405: The aperture is changed. If a flash is being used, some cameras will adjust flash output as well. The earliest reflected-light exposure meters were wide-angle, averaging types, measuring the average scene luminance. Exposure meter calibration was chosen to result in the "best" exposures for typical outdoor scenes; when measuring a single scene element (such as the side of a building in open shade),

1404-408: The arrangement and rendering of various scene elements according to the photographer's desire. Achieving the desired image involves image management (placement of the camera, choice of lens, and possibly the use of camera movements ) and control of image values . The Zone System is concerned with the control of image values, ensuring that light and dark values are rendered as desired. Anticipation of

1456-482: The concept is very simple—render light subjects as light, and dark subjects as dark, according to the photographer's visualization. The Zone System assigns numbers from 0 through 10 to different brightness values, with 0 representing black, 5 middle gray, and 10 pure white; these values are known as zones . To make zones easily distinguishable from other quantities, Adams and Archer used Roman rather than Arabic numerals. Strictly speaking, zones refer to exposure, with

1508-527: The digital image. As with color reversal film, the normal procedure is to expose for the highlights and process for the shadows. Until recently, digital sensors had a much narrower dynamic range than color negative film, which, in turn, has less range than monochrome film. But an increasing number of digital cameras have achieved wider dynamic ranges. One of the first was Fujifilm 's FinePix S3 Pro digital SLR (released in 2004), which has their proprietary " Super CCD SR sensor" specifically developed to overcome

1560-504: The early 1980s (and written with the assistance of Robert Baker) also proved far more comprehensible to the average photographer. The Zone System has often been thought to apply only to certain materials, such as black-and-white sheet film and black-and-white photographic prints. At a time when introduction of electronic still image cameras to the consumer market was imminent (e.g. the Sony Mavica ), Adams (1981, xii) stated I believe

1612-416: The electronic image will be the next major advance. Such systems will have their own inherent and inescapable structural characteristics, and the artist and functional practitioner will again strive to comprehend and control them. which is sometimes interpreted as evidence that Adams envisioned his Zone System to be useful for electronic or even digital image capture/processing. However, in this quotation there

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1664-495: The final result before making the exposure is known as visualization . Any scene of photographic interest contains elements of different luminance ; consequently, the "exposure" actually is many different exposures. The exposure time is the same for all elements, but the image illuminance varies with the luminance of each subject element. Exposure is often determined using a reflected-light exposure meter . The earliest meters measured overall average luminance; meter calibration

1716-399: The highlights. Because of color shifts, color film usually does not lend itself to variations in development time. Use of the Zone System with color film is similar to that with black-and-white roll film, except that the exposure range is somewhat less, so that there are fewer zones between black and white. The exposure scale of color reversal film is less than that of color negative film, and

1768-442: The indicated exposure is in the approximate middle of the film or electronic sensor's exposure range. When measuring a scene with atypical distribution of light and dark elements, or a single element that is lighter or darker than a middle tone, the indicated exposure may not be optimal. For example, a scene with predominantly light tones (e.g., a white horse) often will be underexposed, while a scene with predominantly dark tones (e.g.,

1820-416: The indicated exposure is often needed if the metered scene element is to be rendered as visualized. In the Zone System, measurements are made of individual scene elements, and exposure is adjusted based on the photographer's knowledge of what is being metered: a photographer knows the difference between freshly fallen snow and a black horse, while a meter does not. Much has been written on the Zone System, but

1872-485: The issue of limited dynamic range, using interstitial low-sensitivity photosites (pixels) to capture highlight details. The CCD is thus able to expose at both low and high sensitivities within one shot by assigning a honeycomb of pixels to different intensities of light. Greater scene contrast can be accommodated by making one or more exposures of the same scene using different exposure settings and then combining those images. It often suffices to make two exposures, one for

1924-402: The negative contrast so that the full range of tones is available. This technique is known as expansion , and the development usually referred to as "plus" or "N+". Criteria for plus development vary among different photographers; Adams used it to raise a Zone VII placement to Zone VIII in the print, and referred to it as "N + 1" development. Conversely, if the negative for

1976-410: The number of inks used and the paper on which it is printed. Similarly, the density range of a traditional photographic print depends on the processes used as well as the paper characteristics. Most high-end digital cameras allow viewing a histogram of the tonal distribution of the captured image. This histogram, which shows the concentration of tones, running from dark on the left to light on

2028-399: The physical scene and the print is established by characteristics of the negative and the print. Exposure and development of the negative are usually determined so that a properly exposed negative will yield an acceptable print on a specific photographic paper. Although zones directly relate to exposure, visualization relates to the final result. A black-and-white photographic print represents

2080-499: The print is extremely difficult with normal processing. Adams (1981, 60) described the zone scale and its relationship to typical scene elements: For cinematography, in general, parts of the scene falling in Zone ;III will have textured black, and objects on Zone VII will have textured white. In other words, if the text on a piece of white paper is to be readable, light and expose the white so that it falls on Zone VII. This

2132-430: The print will display as recorded (e.g. Zone V as Zone V, Zone VI as Zone VI, and so on). In general, optimal negative development will be different for every type and grade of paper. It is often desirable for a print to exhibit a full range of tonal values; this may not be possible for a low-contrast scene if the negative is given normal development. However, the development can be increased to increase

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2184-436: The procedure for exposure usually is different, favoring highlights rather than shadows; the shadow values then fall where they will. Whatever the exposure range, the meter indication results in a Zone V placement. Adams (1981, 95–97) described the application to color film, both negative and reversal. The Zone System can be used in digital photography just as in film photography; Adams (1981, xiii) himself anticipated

2236-442: The right, can be used to judge whether a full tonal range has been captured, or whether the exposure should be adjusted, such as by changing the exposure time , lens aperture , or ISO speed , to ensure a tonally rich starting image. The Zone System gained an early reputation for being complex, difficult to understand, and impractical to apply to real-life shooting situations and equipment. Criticism has been raised on grounds that

2288-420: The scene is identified, and that element is placed on the desired zone; the other elements in the scene then fall where they may. With negative film, exposure often favors shadow detail; the procedure then is to For every combination of film, developer, and paper there is a "normal" development time that will allow a properly exposed negative to give a reasonable print. In many cases, this means that values in

2340-535: The shadows, and one for the highlights; the images are then overlapped and blended appropriately , so that the resulting composite represents a wider range of colors and tones. Combining images is often easier if the image-editing software includes features, such as the automatic layer alignment in Adobe Photoshop , that assist precise registration of multiple images. Even greater scene contrast can be handled by using more than two exposures and combining with

2392-404: The tonal range of the final print, producing richer dark tones that still hold shadow detail. His book The Print described using the techniques of dodging and burning to selectively darken or lighten areas of the final print. The Zone System requires that every variable in photography, from exposure to darkroom production of the print, be calibrated and controlled. The print is the last link in

2444-401: The tonal values in that section. Finally, the zones are defined by numbering each section with Roman numerals from 0 for the black section to X for the white one. Adams (1981, 52) distinguished among three different exposure scales for the negative: He noted that negatives can record detail through Zone XII and even higher, but that bringing this information within the exposure scale of

2496-411: The visual world as a series of tones ranging from black to white. Imagine all of the tonal values that can appear in a print, represented as a continuous gradation from black to white: From this starting point, zones are formed by first dividing the tonal gradation into ten equal sections, all one stop apart, plus one more for blown-out paper white. Then for each section, one average tone represents all

2548-461: The white horse is rendered as white. Many modern cameras incorporate metering systems that measure scene contrast as well as average luminance, and employ sophisticated algorithms to infer the appropriate exposure from these data. In scenes with very unusual lighting, however, these metering systems sometimes cannot match the judgment of a skilled photographer, so exposure compensation still may be needed. An early application of exposure compensation

2600-412: Was established to give satisfactory exposures for typical outdoor scenes. However, if the part of a scene that is metered includes large areas of unusually high or low reflectance, or unusually large areas of highlight or shadow, the "effective" average reflectance may differ substantially from that of a "typical" scene, and the rendering may not be as desired. An averaging meter cannot distinguish between

2652-406: Was metered on Zone V (5), a medium gray. The tonal range of color negative film is slightly less than that of black-and-white film, and the tonal range of color reversal film and digital sensors even less; accordingly, there are fewer zones between pure black and pure white. The meter indication, however, remains Zone V. The relationship between exposure compensation and exposure zones

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2704-550: Was the Zone System developed by Ansel Adams and Fred Archer . Although the Zone System has sometimes been regarded as complex, the basic concept is quite simple: render dark objects as dark and light objects as light, according to the photographer's visualization. Developed for black-and-white film, the Zone System divided luminance into 11 zones, with Zone 0 representing pure black and Zone X (10) representing pure white. The meter indication would place whatever

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