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64-482: According to Minolta, development of the TC-1 began when an engineer questioned why SLRs were too bulky to carry day-to-day, but compact cameras sacrificed image quality. It took experienced technicians 45 minutes to assemble a single camera by hand, as the 150+ delicate, miniaturized parts used were not suited for a high-volume assembly line. The outer shell is made of titanium, which gave the camera its name ("Titanium Clad"). It

128-469: A multiple exposure involves a series of shutter cycles, effectively layering a series of photographs in one image. The accumulated photometric exposure ( H v ) is the same so long as the total exposure time is the same. Radiant exposure of a surface , denoted H e ("e" for "energetic", to avoid confusion with photometric quantities) and measured in J/m , is given by where Luminous exposure of

192-432: A surface , denoted H v ("v" for "visual", to avoid confusion with radiometric quantities) and measured in lx⋅s , is given by where If the measurement is adjusted to account only for light that reacts with the photo-sensitive surface, that is, weighted by the appropriate spectral sensitivity , the exposure is still measured in radiometric units (joules per square meter), rather than photometric units (weighted by

256-581: A better ability to record a range of brightness than slide/transparency film or digital. Digital should be considered to be the reverse of print film, with a good latitude in the shadow range, and a narrow one in the highlight area; in contrast to film's large highlight latitude, and narrow shadow latitude. Slide/Transparency film has a narrow latitude in both highlight and shadow areas, requiring greater exposure accuracy. Negative film's latitude increases somewhat with high ISO material, in contrast digital tends to narrow on latitude with high ISO settings. Areas of

320-458: A built-in light meter , or multiple point meters interpreted by a built-in computer, see metering mode . Negative and print film tends to bias for exposing for the shadow areas (film dislikes being starved of light), with digital favouring exposure for highlights. See latitude below. Latitude is the degree by which one can over, or under expose an image, and still recover an acceptable level of quality from an exposure. Typically negative film has

384-462: A difference of 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a stop . The EV concept was developed by the German shutter manufacturer Friedrich Deckel in the 1950s ( Gebele 1958 ; Ray 2000 , 318). Its intent was to simplify choosing among equivalent camera exposure settings by replacing combinations of shutter speed and f-number (e.g., 1/125 s at f /16 ) with

448-499: A greater EV corresponds to greater luminance or illuminance. Illuminance is measured using a flat sensor; if the common value of C = 250 (unit: lux s ISO=lm s/m ISO) is used, an EV of zero (e.g., an aperture of f /1 and a shutter time of 1 sec) for ISO = 100 corresponds to an illuminance of 2.5 lux ( 0.23 fc ). At EV = 15 (the "sunny sixteen" amount of light) the illuminance is 82,000 lux ( 7600 fc ). For general photography, incident-light measurements are usually taken with

512-400: A greater tonality range over conventional methods by varying the contrast of the film to fit the print contrast capability. Digital cameras can achieve similar results ( high dynamic range ) by combining several different exposures (varying shutter or diaphragm) made in quick succession. Today, most cameras automatically determine the correct exposure at the time of taking a photograph by using

576-606: A hemispherical sensor; the readings cannot be meaningfully related to illuminance. An exposure meter may not always be available, and using a meter to determine exposure for some scenes with unusual lighting distribution may be difficult. However, natural light, as well as many scenes with artificial lighting, is predictable, so that exposure often can be determined with reasonable accuracy from tabulated values. Exposure values in Table 2 are reasonable general guidelines, but they should be used with caution. For simplicity, they are rounded to

640-472: A loss of highlight detail, that is, when important bright parts of an image are "washed out" or effectively all white, known as "blown-out highlights" or " clipped whites ". A photograph may be described as underexposed when it has a loss of shadow detail, that is, when important dark areas are "muddy" or indistinguishable from black, known as "blocked-up shadows" (or sometimes "crushed shadows", "crushed blacks", or "clipped blacks", especially in video). As

704-508: A photo where information is lost due to extreme brightness are described as having "blown-out highlights" or "flared highlights". In digital images this information loss is often irreversible, though small problems can be made less noticeable using photo manipulation software . Recording to RAW format can correct this problem to some degree, as can using a digital camera with a better sensor. Film can often have areas of extreme overexposure but still record detail in those areas. This information

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768-407: A reciprocally smaller aperture is required to reduce the amount of light hitting the film to obtain the same exposure. For example, the photographer may prefer to make his sunny-16 shot at an aperture of f /5.6 (to obtain a shallow depth of field). As f /5.6 is 3 stops "faster" than f /16 , with each stop meaning double the amount of light, a new shutter speed of (1/125)/(2·2·2) = 1/1000 s

832-458: A scene with strong or harsh lighting, the ratio between highlight and shadow luminance values may well be larger than the ratio between the film's maximum and minimum useful exposure values. In this case, adjusting the camera's exposure settings (which only applies changes to the whole image, not selectively to parts of the image) only allows the photographer to choose between underexposed shadows or overexposed highlights; it cannot bring both into

896-414: A shutter speed of 1/100 of a second. This is called the sunny 16 rule : at an aperture of f /16 on a sunny day, a suitable shutter speed will be one over the film speed (or closest equivalent). A scene can be exposed in many ways, depending on the desired effect a photographer wishes to convey. An important principle of exposure is reciprocity . If one exposes the film or sensor for a longer period,

960-414: A single number (e.g., 15). On some lenses with leaf shutters , the process was further simplified by allowing the shutter and aperture controls to be linked such that, when one was changed, the other was automatically adjusted to maintain the same exposure. This was especially helpful to beginners with limited understanding of the effects of shutter speed and aperture and the relationship between them. But it

1024-493: A single value. But for many such combinations used in general photography, the ratio gives a fractional value with a large denominator; this is notationally inconvenient as well as difficult to remember. Inverting this ratio and taking the base-2 logarithm allows defining a quantity E v such that resulting in a value that progresses in a linear sequence as camera exposure is changed in power-of-2 steps. For example, beginning with 1 s and f /1 , decreasing exposure gives

1088-587: A working knowledge of exposure values , the APEX system and/or the Zone System . A camera in automatic exposure or autoexposure (usually initialized as AE ) mode automatically calculates and adjusts exposure settings to match (as closely as possible) the subject's mid-tone to the mid-tone of the photograph. For most cameras, this means using an on-board TTL exposure meter . Aperture priority (commonly abbreviated as A , or Av for aperture value ) mode gives

1152-415: Is a stub . You can help Misplaced Pages by expanding it . Exposure value In photography , exposure value ( EV ) is a number that represents a combination of a camera 's shutter speed and f-number , such that all combinations that yield the same exposure have the same EV (for any fixed scene luminance ). Exposure value is also used to indicate an interval on the photographic exposure scale, with

1216-409: Is appropriate to characterize such sensitivity to invisible light. In sensitometric data, such as characteristic curves, the log exposure is conventionally expressed as log 10 ( H ). Photographers more familiar with base-2 logarithmic scales (such as exposure values ) can convert using log 2 ( H ) ≈ 3.32 log 10 ( H ) . "Correct" exposure may be defined as an exposure that achieves

1280-502: Is approximately the same volume as three 35mm film cartridges. The camera operates in aperture-priority autoexposure, with four selectable aperture settings of f /3.5 , 5.6, 8, or 16. Exposure compensation of up to ±4  EV is possible in 1 ⁄ 2  EV steps. One uncommon feature is the diaphragm, which used discrete circular Waterhouse stops rather than a iris with multiple diaphragm blades. It has received praise for its bokeh (out-of-focus characteristics). In 1996,

1344-418: Is controlled in a camera by shutter speed , and the illuminance depends on the lens aperture and the scene luminance . Slower shutter speeds (exposing the medium for a longer period of time), greater lens apertures (admitting more light), and higher-luminance scenes produce greater exposures. An approximately correct exposure will be obtained on a sunny day using ISO 100 film, an aperture of f /16 and

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1408-400: Is determined by shutter speed , lens f-number , and scene luminance . Exposure is measured in units of lux - seconds (symbol lx ⋅ s), and can be computed from exposure value (EV) and scene luminance in a specified region. An "exposure" is a single shutter cycle . For example, a long exposure refers to a single, long shutter cycle to gather enough dim light, whereas

1472-402: Is directly proportional to the area of the aperture, and hence inversely proportional to the square of the lens f-number; thus for constant lighting conditions, the exposure is constant as long as the ratio t / N is constant. If, for example, the f-number is changed, an equivalent exposure time can be determined from Performing this calculation mentally is tedious for most photographers, but

1536-413: Is in "HOLD" position, it is locked and the central button is required to turn the dial to the appropriate manual control. Moving clockwise from "HOLD", the camera provides controls for flash mode (on / off / "night-portrait" or fill ), red-eye reduction, self timer (2 and 10 seconds), ISO (manual film speed), autofocus / manual focus distance, and exposure compensation . A button on the top edge of

1600-435: Is intended to allow the photographer to simply offset the exposure level from the internal meter's estimate of appropriate exposure. Frequently calibrated in stops, also known as EV units , a "+1" exposure compensation setting indicates one stop more (twice as much) exposure and "–1" means one stop less (half as much) exposure. Exposure compensation is particularly useful in combination with auto-exposure mode, as it allows

1664-545: Is just applying the quotient identity of logarithms to the first line. EV 0 corresponds to an exposure time of 1  s and an aperture of f /1.0 . If the EV is known, it can be used to select combinations of exposure time and f-number, as shown in Table ;1. Each increment of 1 in exposure value corresponds to a change of one "step" (or, more commonly, one "stop") in exposure, i.e., half as much exposure, either by halving

1728-428: Is less applicable to scenes with highly atypical luminance distributions, such as city skylines at night. In such situations, the EV that will result in the best picture often is better determined by subjective evaluation of photographs than by formal consideration of luminance or illuminance. For a given luminance and film speed, a greater EV results in less exposure, and for fixed exposure (i.e., fixed camera settings),

1792-429: Is lost during capture. The photographer may carefully overexpose or underexpose the photograph to eliminate "insignificant" or "unwanted" detail; to make, for example, a white altar cloth appear immaculately clean, or to emulate the heavy, pitiless shadows of film noir . However, it is technically much easier to discard recorded information during post processing than to try to 're-create' unrecorded information. In

1856-494: Is made by adjusting one control. Current cameras do not allow direct setting of EV, and cameras with automatic exposure control generally obviate the need for it. EV can nonetheless be helpful when used to transfer recommended exposure settings from an exposure meter (or table of recommended exposures ) to an exposure calculator (or table of camera settings ). Used as an indicator of camera settings, EV corresponds to actual combinations of shutter speed and aperture setting. When

1920-472: Is measured on a scale published by the International Organization for Standardization (ISO). Faster film, that is, film with a higher ISO rating, requires less exposure to make a readable image. Digital cameras usually have variable ISO settings that provide additional flexibility. Exposure is a combination of the length of time and the illuminance at the photosensitive material. Exposure time

1984-407: Is needed. Once the photographer has determined the exposure, aperture stops can be traded for halvings or doublings of speed, within limits. The true characteristic of most photographic emulsions is not actually linear (see sensitometry ), but it is close enough over the exposure range of about 1 second to 1/1000 of a second. Outside of this range, it becomes necessary to increase the exposure from

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2048-582: Is to estimate the subject's mid-tone luminance and indicate the camera exposure settings required to record this as a mid-tone. In order to do this it has to make a number of assumptions which, under certain circumstances, will be wrong. If the exposure setting indicated by an exposure meter is taken as the "reference" exposure, the photographer may wish to deliberately overexpose or underexpose in order to compensate for known or anticipated metering inaccuracies. Cameras with any kind of internal exposure meter usually feature an exposure compensation setting which

2112-400: The acronym EV is more common elsewhere . The Exif standard uses Ev ( CIPA 2016 ). Although all camera settings with the same EV nominally give the same exposure, they do not necessarily give the same picture. The f-number (relative aperture ) determines the depth of field , and the shutter speed ( exposure time ) determines the amount of motion blur , as illustrated by the two images at

2176-433: The difference between the indicated and set exposures. For example, an exposure compensation of +1 EV (or +1 step) means to increase exposure, by using either a longer exposure time or a smaller f-number. Exposure (photography)#Automatic exposure In photography , exposure is the amount of light per unit area reaching a frame of photographic film or the surface of an electronic image sensor . It

2240-683: The Camera Journal Press Club of Japan awarded the TC-1 with the Camera Grand Prix. A special edition for the Japanese domestic market, finished in black, was built to celebrate Minolta's 70th anniversary in 1998 and limited to 2500 examples. As part of the same anniversary, 2000 examples of the G-Rokkor lens from the TC-1 were sold as a limited-production interchangeable lens in M39 lens mount ; unlike

2304-451: The TC-1, the M39 version of the G-Rokkor was equipped with a 9-blade iris diaphragm, offering the additional aperture settings of f /4 , 11, and 22. All versions of the TC-1 were discontinued by 2007 and has become collectible since then. The TC-1 controls and display are provided on the top panel, with the exception of the aperture selector lever, which is on the lens. A small leather patch on

2368-450: The actual EV matches that recommended by the light level and the ISO speed, these settings should result in the "correct" exposure. "Correct" exposure is obtained when the f-number and exposure time match those "recommended" for given lighting conditions and ISO speed; the relationship is given by the exposure equation prescribed by ISO 2720:1974 : where Applied to the right-hand side of

2432-422: The adjacent image shows, these terms are technical ones rather than artistic judgments; an overexposed or underexposed image may be "correct" in the sense that it provides the effect that the photographer intended. Intentionally over- or underexposing (relative to a standard or the camera's automatic exposure) is casually referred to as " exposing to the right " or "exposing to the left" respectively, as these shift

2496-471: The calculated value to account for this characteristic of the emulsion. This characteristic is known as reciprocity failure . The film manufacturer's data sheets should be consulted to arrive at the correction required, as different emulsions have different characteristics. Digital camera image sensors can also be subject to a form of reciprocity failure. The Zone System is another method of determining exposure and development combinations to achieve

2560-473: The camera for EV 11 allows shooting night sports at a light level of EV 100 = 9, in agreement with the example done the other way around above. An online calculator that implemented this calculation was available at dpreview.com . On most cameras, there is no direct way to transfer an EV to camera settings; however, a few cameras, such as some Voigtländer and Braun models or the Kodak Pony II shown in

2624-459: The effect the photographer intended. A more technical approach recognises that a photographic film (or sensor) has a physically limited useful exposure range , sometimes called its dynamic range . If, for any part of the photograph, the actual exposure is outside this range, the film cannot record it accurately. In a very simple model, for example, out-of-range values would be recorded as "black" (underexposed) or "white" (overexposed) rather than

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2688-441: The equation is easily solved with a calculator dial on an exposure meter ( Ray 2000 , 318) or a similar dial on a standalone calculator. If the camera controls have detents, constant exposure can be maintained by counting the steps as one control is adjusted and counting an equivalent number of steps when adjusting the other control. The ratio t / N could be used to represent equivalent combinations of exposure time and f-number in

2752-484: The exposure equation is where In terms of exposure value, the right-hand side becomes When applied to the left-hand side of the exposure equation, EV denotes actual combinations of camera settings; when applied to the right-hand side, EV denotes combinations of camera settings required to give the nominally "correct" exposure. The formal relationship of EV to luminance or illuminance has limitations. Although it usually works well for typical outdoor scenes in daylight, it

2816-440: The exposure equation, exposure value is If the common value of K = 12.5 (unit: cd s/m ISO) is used, an EV of zero (e.g., an aperture of f /1 and a shutter time of 1 sec) for ISO = 100 corresponds to a luminance of 0.125 cd/m ( 0.01 cd/ft ). At EV = 15 (the " sunny sixteen " amount of light) the luminance is 4096 cd/m ( 380 cd/ft ). Camera settings also can be determined from incident-light measurements, for which

2880-405: The exposure time or halving the aperture area, or a combination of such changes. Greater exposure values are appropriate for photography in more brightly lit situations, or for lower ISO speeds . "Exposure value" indicates combinations of camera settings rather than the luminous exposure (aka photometric exposure), which is given by ( Ray 2000 , 310) where The illuminance E is controlled by

2944-422: The exposure values (decrease the exposures) by the number of exposure steps by which that speed is greater than ISO 100, formally For example, ISO 400 speed is two steps greater than ISO 100: To photograph outdoor night sports with an ISO 400–speed imaging medium, search Table 2 for "Night sports" (which has an EV of 9 for ISO 100), and add 2 to get EV 400  = 11 . For lower ISO speed, decrease

3008-514: The exposure values (increase the exposures) by the number of exposure steps by which the speed is less than ISO 100. For example, ISO 50 speed is one step less than ISO 100: To photograph a rainbow against a cloudy sky with an ISO 50–speed imaging medium, search Table 2 for "Rainbows-Cloudy sky background" (which has an EV of 14), and subtract 1 to get EV 50  = 13 . The equation for correcting for ISO speed can also be solved for EV 100 : For example, using ISO 400 film and setting

3072-522: The f-number but also depends on the scene luminance . To avoid confusion, some authors ( Ray 2000 , 310) have used camera exposure to refer to combinations of camera settings. The 1964 ASA standard for automatic exposure controls for cameras, ASA PH2.15-1964 , took the same approach, and also used the more descriptive term camera exposure settings . Common practice among photographers is nonetheless to use "exposure" to refer to camera settings as well as to photometric exposure. The image-plane illuminance

3136-465: The features became available on cameras in the United States ( Desfor 1957 ). Because of mechanical considerations, the coupling of shutter and aperture was limited to lenses with leaf shutters; however, various automatic exposure modes now work to somewhat the same effect in cameras with focal-plane shutters . The proper EV was determined by the scene luminance and film speed; it was intended that

3200-405: The front of the camera facilitates grip by the right hand. The button furthest to the right, when the camera is held by the photographer, is the shutter release. The photographer's right index finger is intended to select the aperture, then use the shutter release button. On the front edge of the camera is a slider which adjusts settings according to the position of the control dial. When the dial

3264-512: The histogram of the image to the right or left. In manual mode, the photographer adjusts the lens aperture and/or shutter speed to achieve the desired exposure. Many photographers choose to control aperture and shutter independently because opening up the aperture increases exposure, but also decreases the depth of field , and a slower shutter increases exposure but also increases the opportunity for motion blur . "Manual" exposure calculations may be based on some method of light metering with

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3328-450: The locking was optional, so that the photographer could choose the preferred method of working depending on the situation. Use of EV on some meters and cameras is discussed briefly by Adams (1981 , 39). He notes that, in some cases, the EV indication from the meter may need to be adjusted for film speed. Many current cameras allow for exposure compensation , and usually state it in terms of EV ( Ray 2000 , 316). In this context, EV refers to

3392-507: The nearest integer, and they omit numerous considerations described in the ANSI exposure guides from which they are derived. Moreover, they take no account of color shifts or reciprocity failure. Proper use of tabulated exposure values is explained in detail in the ANSI exposure guide, ANSI PH2.7-1986 . The exposure values in Table 2 are for ISO 100 speed ("EV 100 "). For a different ISO speed S {\displaystyle S} , increase

3456-485: The nominal sensitivity of the human eye). Only in this appropriately weighted case does the H measure the effective amount of light falling on the film, such that the characteristic curve will be correct independent of the spectrum of the light. Many photographic materials are also sensitive to "invisible" light, which can be a nuisance (see UV filter and IR filter ), or a benefit (see infrared photography and full-spectrum photography ). The use of radiometric units

3520-424: The photo, allowed direct setting of exposure value. Some medium-format cameras from Rollei ( Rolleiflex , Rolleicord models) and Hasselblad allowed EV to be set on the lenses. The set EV could be locked, coupling shutter and aperture settings, such that adjusting either the shutter speed or aperture made a corresponding adjustment in the other to maintain a constant exposure ( Ray 2000 , 318). On some lenses

3584-477: The photographer manual control of the aperture, whilst the camera automatically adjusts the shutter speed to achieve the exposure specified by the TTL meter. Shutter priority (often abbreviated as S , or Tv for time value ) mode gives manual shutter control, with automatic aperture compensation. In each case, the actual exposure level is still determined by the camera's exposure meter. The purpose of an exposure meter

3648-401: The photographer to bias the exposure level without resorting to full manual exposure and losing the flexibility of auto exposure. On low-end video camcorders, exposure compensation may be the only manual exposure control available. An appropriate exposure for a photograph is determined by the sensitivity of the medium used. For photographic film, sensitivity is referred to as film speed and

3712-406: The precisely graduated shades of colour and tone required to describe "detail". Therefore, the purpose of exposure adjustment (and/or lighting adjustment) is to control the physical amount of light from the subject that is allowed to fall on the film, so that 'significant' areas of shadow and highlight detail do not exceed the film's useful exposure range. This ensures that no 'significant' information

3776-422: The rear panel, just under the control dial, engages the spot meter. The button between the setting adjustment slider and dial resets the focus mode to autofocus. On the left edge of the camera, a backlit LCD display provides feedback on settings while they are being adjusted. Illumination is turned on by a button just below the display on the top edge of the camera's back. This photography-related article

3840-704: The right (and at long exposure times, as a second-order effect, the light-sensitive medium may exhibit reciprocity failure , which is a change of light sensitivity dependent on the irradiance at the film). Exposure value is a base-2 logarithmic scale defined by ( Ray 2000, 318 ): E V = log 2 ⁡ N 2 t = 2 log 2 ⁡ N − log 2 ⁡ t , {\displaystyle {\begin{aligned}\mathrm {EV} &=\log _{2}{\frac {N^{2}}{t}}\\&=2\log _{2}{N}-\log _{2}{t}\,,\end{aligned}}} where The second line

3904-420: The simple sequence The last two values shown frequently apply when using ISO 100 speed imaging media in outdoor photography. This system provides its greatest benefit when using an exposure meter (or table) calibrated in EV with a camera that allows settings to be made in EV, especially with coupled shutter and aperture; the appropriate exposure is easily set on the camera, and choosing among equivalent settings

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3968-477: The system also include adjustment for filters, exposure compensation, and other variables. With all of these elements included, the camera would be set by transferring the single number thus determined. Exposure value has been indicated in various ways. The ASA and ANSI standards used the quantity symbol E v , with the subscript v indicating the logarithmic value; this symbol continues to be used in ISO standards , but

4032-524: The useful exposure range at the same time. Methods for dealing with this situation include: using what is called fill lighting to increase the illumination in shadow areas; using a graduated neutral-density filter , flag, scrim, or gobo to reduce the illumination falling upon areas deemed too bright; or varying the exposure between multiple, otherwise identical, photographs ( exposure bracketing ) and then combining them afterwards in an HDRI process. A photograph may be described as overexposed when it has

4096-577: Was also useful for experienced photographers who might choose a shutter speed to stop motion or an f-number for depth of field, because it allowed for faster adjustment—without the need for mental calculations—and reduced the chance of error when making the adjustment. The concept became known as the Light Value System (LVS) in Europe; it was generally known as the Exposure Value System (EVS) when

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