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| [[File:High speed03.jpg|thumb|Fast shutter speed, short exposure of a water wave.]]
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| [[File:Slow speed03.jpg|thumb|Slow shutter speed, long exposure of the wave.]]
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| 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 (photography)|exposure]] have the same EV value (for any fixed scene [[luminance]]). Exposure value also is used to indicate an interval on the photographic exposure scale, with 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a '''stop'''.<ref>In optics, the term "stop" properly refers to the aperture itself, while the term "step" refers to a division of the exposure scale. Some authors, e.g., [[#CITEREFDavis1999|Davis (1999]], 13), prefer the term "stop"because they refer to steps (e.g., on a step tablet)
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| that are other than powers of 2. ISO standards generally use "step", while photographers normally use "stop".</ref>
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| The EV concept was developed in an attempt to simplify choosing among combinations of equivalent camera settings, by the German shutter manufacturer {{ill|de|Friedrich Deckel|Friedrich Deckel}} in the 1950s ([[#CITEREFRay2000|Ray 2000]], 318)<!-- This reference speaks about "1950s in Germany", not about Deckel specifically. Various Deckel patents exist, f.e. BP 744962 in 1952/1956 by Hans Deckel and Friedrich Wilhelm Deckel, US patent 2911897 in 1955/1959 by Christoph Fahl, Hans Deckel and Friedrich Wilhelm Deckel. -->. Exposure value was originally indicated by the quantity symbol <math>E_v</math>; this symbol continues to be used in [[ISO standard]]s, but the [[acronym]] EV is [[Photographers' abbreviations|more common elsewhere]].
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| 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 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).
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| ==Formal definition==
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| [[File:Spinning into Action.jpg|thumb|Extended exposure time of 26 seconds.]]
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| Exposure value is a base-2 [[logarithm]]ic scale defined by [[#CITEREFRay2000|Ray (2000, p. 318)]]:
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| :<math>\mathrm {EV} = \log_2 {\frac {N^2} {t} } \,,</math>
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| where
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| * ''N'' is the relative [[aperture]] ([[f-number]])
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| * ''t'' is the exposure time (“[[shutter speed]]”) in seconds<ref name="no_units">In a mathematical expression involving physical quantities, it is common practice to require that the argument to a [[transcendental function]] (such as the [[logarithm]]) be [[dimensionless]]. The definition of EV ignores the units in the denominator and uses only the [[ISO 31-0#Quantities and units|numerical value]] of the exposure time in seconds; EV is not the expression of a physical law, but simply a number for encoding combinations of camera settings.</ref><!-- TBD: I guess this can be improved to have a mathmatically correct formula here. -->
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| EV 0 corresponds to an exposure time of 1 [[second|s]] and a relative aperture of <var>f</var>/1.0.
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| If the EV is known, it can be used to select combinations of exposure time and <var>f</var>-number, as shown in Table 1.
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| <!-- TBD. The following sentence apparently still causes confusion amongst readers and should be further improved for clarification. -->
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| 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 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 higher [[film speed|ISO speed]]s.
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| ==Camera settings vs. photometric exposure==
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| [[File:Shutter with EV scale.png|thumb|Shutter with EV indicator, figure from US patent 2829574, Inventor: K. Gebele, original assignee: Hans Deckel, filing date: Nov 2, 1953, issue date: Apr 8, 1958]]
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| "Exposure value" actually indicates combinations of camera settings rather than the [[Photometry (optics)|photometric]] quantity of luminous exposure ''H''<sub>v</sub> (aka photometric exposure), which is given by ([[#CITEREFRay2000|Ray 2000]], 310)
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| :<math>H_\mathrm{v} = E_\mathrm{v} \cdot t \,,</math>
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| where
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| * ''H''<sub>v</sub> is the [[photometric exposure|photometric]] / [[luminous exposure]]
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| * ''E''<sub>v</sub> is the image-plane [[illuminance]] ('''not''' EV, the exposure value)
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| * ''t'' is the exposure time
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| The illuminance ''E''<sub>v</sub> is controlled by the <var>f</var>-number but also depends on the scene [[luminance]] ''L''<sub>v</sub>. To avoid confusion, some authors ([[#CITEREFRay2000|Ray 2000]], 310) have used '''camera exposure''' to refer to combinations of camera settings. The 1964 ASA standard for automatic exposure controls for cameras, [[#CITEREFASA PH2.15-1964|ASA PH2.15-1964]], took the same approach, and also used the more descriptive term '''camera exposure settings'''. | |
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| Common practice among photographers is nonetheless to use “exposure” to refer to camera settings as well as to photometric exposure.
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| ==EV as an indicator of camera settings==
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| EV corresponds simply to a combination of a shutter speed and an aperture setting, independent of any ISO setting—independent even of whether there is film in the camera or any light available.
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| :{| class="wikitable" style="text-align: right;"
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| |+ Table 1. Exposure times, in seconds or minutes (m), for various exposure values and <var>f</var>-numbers
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| ! rowspan="2" style="padding: 0.1em 0.5em;" | EV
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| ! colspan="13" | <var>f</var>-number
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| |-
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| ! 1.0 !! 1.4 !! 2.0 !! 2.8 !! 4.0 !! 5.6 !! 8.0 !! 11 !! 16 !! 22 !! 32 !! 45 !! 64
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| |-
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| ! style="text-align: right; padding: 0.1em 0.5em;" | −6
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| | style="padding: 0.1em 0.5em;" | 60
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| | style="padding: 0.1em 0.5em;" | 2 m
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| | style="padding: 0.1em 0.5em;" | 4 m
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| | style="padding: 0.1em 0.5em;" | 8 m
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| | style="padding: 0.1em 0.5em;" | 16 m
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| | style="padding: 0.1em 0.5em;" | 32 m
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| | style="padding: 0.1em 0.5em;" | 64 m
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| | style="padding: 0.1em 0.5em;" | 128 m
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| | style="padding: 0.1em 0.5em;" | 256 m
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| | style="padding: 0.1em 0.5em;" | 512 m
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| | style="padding: 0.1em 0.5em;" | 1024 m
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| | style="padding: 0.1em 0.5em;" | 2048 m
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| | style="padding: 0.1em 0.5em;" | 4096 m
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| |-
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| ! style="text-align: right; padding: 0.1em 0.5em;" | −5
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| | style="padding: 0.1em 0.5em;" | 30
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| | style="padding: 0.1em 0.5em;" | 60
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| | style="padding: 0.1em 0.5em;" | 2 m
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| | style="padding: 0.1em 0.5em;" | 4 m
| |
| | style="padding: 0.1em 0.5em;" | 8 m
| |
| | style="padding: 0.1em 0.5em;" | 16 m
| |
| | style="padding: 0.1em 0.5em;" | 32 m
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| | style="padding: 0.1em 0.5em;" | 64 m
| |
| | style="padding: 0.1em 0.5em;" | 128 m
| |
| | style="padding: 0.1em 0.5em;" | 256 m
| |
| | style="padding: 0.1em 0.5em;" | 512 m
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| | style="padding: 0.1em 0.5em;" | 1024 m
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| | style="padding: 0.1em 0.5em;" | 2048 m
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | −4
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| | style="padding: 0.1em 0.5em;" | 15
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| | style="padding: 0.1em 0.5em;" | 30
| |
| | style="padding: 0.1em 0.5em;" | 60
| |
| | style="padding: 0.1em 0.5em;" | 2 m
| |
| | style="padding: 0.1em 0.5em;" | 4 m
| |
| | style="padding: 0.1em 0.5em;" | 8 m
| |
| | style="padding: 0.1em 0.5em;" | 16 m
| |
| | style="padding: 0.1em 0.5em;" | 32 m
| |
| | style="padding: 0.1em 0.5em;" | 64 m
| |
| | style="padding: 0.1em 0.5em;" | 128 m
| |
| | style="padding: 0.1em 0.5em;" | 256 m
| |
| | style="padding: 0.1em 0.5em;" | 512 m
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| | style="padding: 0.1em 0.5em;" | 1024 m
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | −3
| |
| | style="padding: 0.1em 0.5em;" | 8
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| | style="padding: 0.1em 0.5em;" | 15
| |
| | style="padding: 0.1em 0.5em;" | 30
| |
| | style="padding: 0.1em 0.5em;" | 60
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| | style="padding: 0.1em 0.5em;" | 2 m
| |
| | style="padding: 0.1em 0.5em;" | 4 m
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| | style="padding: 0.1em 0.5em;" | 8 m
| |
| | style="padding: 0.1em 0.5em;" | 16 m
| |
| | style="padding: 0.1em 0.5em;" | 32 m
| |
| | style="padding: 0.1em 0.5em;" | 64 m
| |
| | style="padding: 0.1em 0.5em;" | 128 m
| |
| | style="padding: 0.1em 0.5em;" | 256 m
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| | style="padding: 0.1em 0.5em;" | 512 m
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | −2
| |
| | style="padding: 0.1em 0.5em;" | 4
| |
| | style="padding: 0.1em 0.5em;" | 8
| |
| | style="padding: 0.1em 0.5em;" | 15
| |
| | style="padding: 0.1em 0.5em;" | 30
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| | style="padding: 0.1em 0.5em;" | 60
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| | style="padding: 0.1em 0.5em;" | 2 m
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| | style="padding: 0.1em 0.5em;" | 4 m
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| | style="padding: 0.1em 0.5em;" | 8 m
| |
| | style="padding: 0.1em 0.5em;" | 16 m
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| | style="padding: 0.1em 0.5em;" | 32 m
| |
| | style="padding: 0.1em 0.5em;" | 64 m
| |
| | style="padding: 0.1em 0.5em;" | 128 m
| |
| | style="padding: 0.1em 0.5em;" | 256 m
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | −1
| |
| | style="padding: 0.1em 0.5em;" | 2
| |
| | style="padding: 0.1em 0.5em;" | 4
| |
| | style="padding: 0.1em 0.5em;" | 8
| |
| | style="padding: 0.1em 0.5em;" | 15
| |
| | style="padding: 0.1em 0.5em;" | 30
| |
| | style="padding: 0.1em 0.5em;" | 60
| |
| | style="padding: 0.1em 0.5em;" | 2 m
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| | style="padding: 0.1em 0.5em;" | 4 m
| |
| | style="padding: 0.1em 0.5em;" | 8 m
| |
| | style="padding: 0.1em 0.5em;" | 16 m
| |
| | style="padding: 0.1em 0.5em;" | 32 m
| |
| | style="padding: 0.1em 0.5em;" | 64 m
| |
| | style="padding: 0.1em 0.5em;" | 128 m
| |
| |-
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| ! style="text-align: right; padding: 0.1em 0.5em;" | 0
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| | style="padding: 0.1em 0.5em;" | 1
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| | style="padding: 0.1em 0.5em;" | 60
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| | style="padding: 0.1em 0.5em;" | 2 m
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| | style="padding: 0.1em 0.5em;" | 4 m
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| | style="padding: 0.1em 0.5em;" | 8 m
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| | style="padding: 0.1em 0.5em;" | 16 m
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| | style="padding: 0.1em 0.5em;" | 32 m
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| | style="padding: 0.1em 0.5em;" | 64 m
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| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| | style="padding: 0.1em 0.5em;" | 1/4
| |
| | style="padding: 0.1em 0.5em;" | 1/2
| |
| | style="padding: 0.1em 0.5em;" | 1
| |
| | style="padding: 0.1em 0.5em;" | 2
| |
| | style="padding: 0.1em 0.5em;" | 4
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 11
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| | style="padding: 0.1em 0.5em;" | 1/4
| |
| | style="padding: 0.1em 0.5em;" | 1/2
| |
| | style="padding: 0.1em 0.5em;" | 1
| |
| | style="padding: 0.1em 0.5em;" | 2
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 12
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| | style="padding: 0.1em 0.5em;" | 1/4
| |
| | style="padding: 0.1em 0.5em;" | 1/2
| |
| | style="padding: 0.1em 0.5em;" | 1
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 13
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| | style="padding: 0.1em 0.5em;" | 1/4
| |
| | style="padding: 0.1em 0.5em;" | 1/2
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 14
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| | style="padding: 0.1em 0.5em;" | 1/4
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 15
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| | style="padding: 0.1em 0.5em;" | 1/8
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 16
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| | style="padding: 0.1em 0.5em;" | 1/15
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 17
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| | style="padding: 0.1em 0.5em;" | 1/30
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 18
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| | style="padding: 0.1em 0.5em;" | 1/60
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 19
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| | style="padding: 0.1em 0.5em;" | 1/125
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 20
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| | style="padding: 0.1em 0.5em;" | 1/250
| |
| |-
| |
| ! style="text-align: right; padding: 0.1em 0.5em;" | 21
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" |
| |
| | style="padding: 0.1em 0.5em;" | 1/8000
| |
| | style="padding: 0.1em 0.5em;" | 1/4000
| |
| | style="padding: 0.1em 0.5em;" | 1/2000
| |
| | style="padding: 0.1em 0.5em;" | 1/1000
| |
| | style="padding: 0.1em 0.5em;" | 1/500
| |
| |-
| |
| ! rowspan="2" style="padding: 0.1em 0.5em;" | EV
| |
| ! 1.0 !! 1.4 !! 2.0 !! 2.8 !! 4.0 !! 5.6 !! 8.0 !! 11 !! 16 !! 22 !! 32 !! 45 !! 64
| |
| |-
| |
| ! colspan="13" | <var>f</var>-number
| |
| |-
| |
| |}
| |
| | |
| [[File:Exposure program chart.gif|thumb|600px|none|Popular exposure chart type, showing exposure values EV (red lines) as combinations of [[aperture]] and [[Shutter (photography)|shutter]] speed values. The green lines are sample program lines, by which a [[digital camera]] automatically selects both the shutter speed and the aperture for given exposure value (brightness of light), when set to [[List of digital camera modes|Program mode (P)]].<sup>[[#CITEREFCanonWWW|Canon]]</sup>]]
| |
| | |
| ==Tabulated exposure values==
| |
| | |
| 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.
| |
| | |
| : '''Table 2. Exposure values (ISO 100 speed) for various lighting conditions'''<ref>
| |
| Exposure values in Table 2 are taken from ANSI exposure
| |
| guides [[#CITEREFANSI PH2.7-1973|PH2.7-1973]] and
| |
| [[#CITEREFANSI PH2.7-1986|PH2.7-1986]]; where the two guides differ, ranges of values have been given or extended.
| |
| The ANSI guides were derived from studies by [[Loyd Ancile Jones]] and H.R. Condit, described in
| |
| [[#CITEREFJonesCondit1941|Jones and Condit (1941)]],
| |
| [[#CITEREFJonesCondit1948|Jones and Condit (1948)]], and
| |
| [[#CITEREFJonesCondit1949|Jones and Condit (1949)]].</ref>
| |
| :{| class="wikitable" style="padding: 0.1em 0.5em; text-align: left"
| |
| |-
| |
| ! Lighting Condition || EV<sub>100</sub>
| |
| |-
| |
| ! colspan="2" | Daylight
| |
| |-
| |
| | | Light sand or snow in full or slightly hazy sunlight (distinct shadows)<sup>a</sup>
| |
| | style="text-align: center;" | 16
| |
| |-
| |
| | | Typical scene in full or slightly hazy sunlight (distinct shadows)<sup>a, b</sup>
| |
| | style="text-align: center;" | 15
| |
| |-
| |
| | | Typical scene in hazy sunlight (soft shadows)
| |
| | style="text-align: center;" | 14
| |
| |-
| |
| | | Typical scene, cloudy bright (no shadows)
| |
| | style="text-align: center;" | 13
| |
| |-
| |
| | | Typical scene, heavy overcast
| |
| | style="text-align: center;" | 12
| |
| |-
| |
| | | Areas in open shade, clear sunlight
| |
| | style="text-align: center;" | 12
| |
| |-
| |
| ! colspan="2" | Outdoor, Natural light
| |
| |-
| |
| | colspan="2" | Rainbows
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Clear sky background
| |
| | style="text-align: center;" | 15
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Cloudy sky background
| |
| | style="text-align: center;" | 14
| |
| |-
| |
| | colspan="2" | Sunsets and skylines
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Just before sunset
| |
| | style="text-align: center;" | 12–14
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | At sunset
| |
| | style="text-align: center;" | 12
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Just after sunset
| |
| | style="text-align: center;" | 9–11
| |
| |-
| |
| | colspan="2" | The Moon,<sup>c</sup> [[altitude (astronomy)|altitude]] > 40°
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Full
| |
| | style="text-align: center;" | 15
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Gibbous
| |
| | style="text-align: center;" | 14
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Quarter
| |
| | style="text-align: center;" | 13
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Crescent
| |
| | style="text-align: center;" | 12
| |
| |-
| |
| | colspan="2" | Moonlight, Moon altitude > 40°
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Full
| |
| | style="text-align: center;" | −3 to −2
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Gibbous
| |
| | style="text-align: center;" | −4
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Quarter
| |
| | style="text-align: center;" | −6
| |
| |-
| |
| | colspan="2" | Aurora borealis and australis
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Bright
| |
| | style="text-align: center;" | −4 to −3
| |
| |-
| |
| | style="padding: 0.1em 1.5em;" | Medium
| |
| | style="text-align: center;" | −6 to −5
| |
| |-
| |
| | | Milky Way galactic center
| |
| | style="text-align: center;" | −11 to −9
| |
| |-
| |
| ! colspan="2" | Outdoor, Artificial Light
| |
| |-
| |
| | | Neon and other bright signs
| |
| | style="text-align: center;" | 9–10
| |
| |-
| |
| | | Night sports
| |
| | style="text-align: center;" | 9
| |
| |-
| |
| | | Fires and burning buildings
| |
| | style="text-align: center;" | 9
| |
| |-
| |
| | | Bright street scenes
| |
| | style="text-align: center;" | 8
| |
| |-
| |
| | | Night street scenes and window displays
| |
| | style="text-align: center;" | 7–8
| |
| |-
| |
| | | Night vehicle traffic
| |
| | style="text-align: center;" | 5
| |
| |-
| |
| | | Fairs and amusement parks
| |
| | style="text-align: center;" | 7
| |
| |-
| |
| | | Christmas tree lights
| |
| | style="text-align: center;" | 4–5
| |
| |-
| |
| | | Floodlit buildings, monuments, and fountains
| |
| | style="text-align: center;" | 3–5
| |
| |-
| |
| | | Distant views of lighted buildings
| |
| | style="text-align: center;" | 2
| |
| |-
| |
| ! colspan="2" | Indoor, Artificial Light
| |
| |-
| |
| | | Galleries
| |
| | style="text-align: center;" | 8–11
| |
| |-
| |
| | | Sports events, stage shows, and the like
| |
| | style="text-align: center;" | 8–9
| |
| |-
| |
| | | Circuses, floodlit
| |
| | style="text-align: center;" | 8
| |
| |-
| |
| | | Ice shows, floodlit
| |
| | style="text-align: center;" | 9
| |
| |-
| |
| | | Offices and work areas
| |
| | style="text-align: center;" | 7–8
| |
| |-
| |
| | | Home interiors
| |
| | style="text-align: center;" | 5–7
| |
| |-
| |
| | | Christmas tree lights
| |
| | style="text-align: center;" | 4–5
| |
| |}
| |
| | |
| <ol type="a">
| |
| <li>Values for direct sunlight apply between approximately two hours after
| |
| sunrise and two hours before sunset, and assume front lighting. As a
| |
| rough general rule, decrease EV by 1 for side lighting, and decrease EV
| |
| by 2 for back lighting</li>
| |
| <li>This is approximately the value given by the [[sunny 16]] rule.</li>
| |
| <li>These values are appropriate for pictures of the Moon taken at night
| |
| with a long lens or telescope, and will render the Moon as a medium
| |
| tone. They will not, in general, be suitable for landscape pictures
| |
| that include the Moon. In a landscape photograph, the Moon typically
| |
| is near the horizon, where its luminance changes considerably with
| |
| [[altitude (astronomy)|altitude]]. Moreover, a landscape photograph
| |
| usually must take account of the sky and foreground as well as the
| |
| Moon. Consequently, it is nearly impossible to give a single correct
| |
| exposure value for such a situation.</li>
| |
| </ol> | |
| | |
| Exposure values in Table 2 are reasonable general guidelines, but they
| |
| should be used with caution. For simplicity, they are rounded to 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 (photography)|reciprocity]]
| |
| failure. Proper use of tabulated exposure values is explained in detail in
| |
| the ANSI exposure guide, [[#CITEREFANSI PH2.7-1986|ANSI PH2.7-1986]].
| |
| | |
| The exposure values in Table 2 are for ISO 100 speed
| |
| ("EV<sub>100</sub>"). For a different ISO speed <math>S</math>,
| |
| increase the exposure values (decrease the exposures) by the number of exposure steps by which that speed is greater than
| |
| ISO 100, formally
| |
| | |
| :<math>\mathrm{EV}_{S} = \mathrm{EV}_{100} + \log_2 \frac {S} {100} \,.</math>
| |
| | |
| For example, ISO 400 speed is two steps greater than ISO 100:
| |
| | |
| :<math>\mathrm{EV}_{400} = \mathrm{EV}_{100} + \log_2 \frac {400} {100}
| |
| = \mathrm{EV}_{100} + 2 \,.</math>
| |
| | |
| 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
| |
| {{nowrap|1=EV<sub>400</sub> = 11}}.
| |
| | |
| For lower ISO speed, decrease 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:
| |
| | |
| :<math>\mathrm{EV}_{50} = \mathrm{EV}_{100} + \log_2 \frac {50} {100}
| |
| = \mathrm{EV}_{100} - 1 \,.</math>
| |
| | |
| 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
| |
| {{nowrap|1=EV<sub>50</sub> = 13}}.
| |
| | |
| The equation for correcting for ISO speed is sometimes shown with a minus sign, and an online calculator implements that version at dpreview.com.<ref name=dpreview>[http://www.dpreview.com/glossary/exposure/exposure Exposure at dpreview.com]</ref> In that case, the value being calculated is an EV<sub>100</sub> or light value (LV),<ref name=dpreview/> a represenation of light meter reading or light level appropriate to the camera EV setting at the given speed:
| |
| | |
| :<math>\mathrm{EV}_{100} = \mathrm{EV}_{S} - \log_2 \frac {S} {100} \,.</math>
| |
| | |
| For example, setting the camera for EV 11 and using ISO 400 films allows shooting night sports at a light level of EV<sub>100</sub> = 9, in agreement with the example done the other way around above.
| |
| | |
| ==Setting EV on a camera==
| |
| [[File:Kodak Pony II Camera.jpg|left|thumb|A Kodak Pony II camera with exposure value setting ring]]
| |
| On most cameras, there is no direct way to transfer an EV to camera settings; however, a few cameras, such as some [[Voigtländer]] and [[Carl Braun Camera-Werk|Braun]] models or the [[Kodak]] Pony II shown in the photo, allowed direct setting of exposure value.
| |
| [[File:Hasselblad with Planar 80mm at EV 12.jpg|right|thumb|Hasselblad Planar 80mm with EVS set at EV 12]]
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| 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. On some lenses the locking was optional, so that the photographer could choose the preferred method of working depending on the situation. Use of the EV scale on Hasselblad cameras is discussed briefly by [[#CITEREFAdams1981|Adams (1981)]], 39).
| |
| | |
| ==Exposure compensation in EV==
| |
| | |
| Many current cameras allow for [[exposure compensation]], and usually state it in terms of EV ([[#CITEREFRay2000|Ray 2000]], 316). In this context, EV refers to 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 <math>f</math>-number.
| |
| | |
| The sense of exposure compensation is opposite that of the EV scale itself.
| |
| An ''increase'' in exposure corresponds to a ''decrease'' in EV, so an exposure compensation of
| |
| +1 EV results in a smaller EV;
| |
| conversely, an exposure compensation of −1 EV results in a greater EV. For example, if a meter
| |
| reading of a lighter-than-normal subject indicates EV 16, and an exposure compensation of +1 EV
| |
| is applied to render the subject appropriately, the final camera settings will correspond to EV 15.
| |
| | |
| ==Meter indication in EV==
| |
| | |
| Some [[light meter]]s (e.g., Pentax [[spot meter]]s) indicate directly in
| |
| EV at ISO 100. Some other meters, especially digital models, can indicate
| |
| EV for the selected ISO speed. In most cases, this difference is
| |
| irrelevant; with the Pentax meters, camera settings usually are determined
| |
| using the exposure calculator, and most digital meters directly display
| |
| shutter speeds and <math>f</math>-numbers.
| |
| | |
| Recently, articles on many web sites have used ''[[light value]]'' (LV) to
| |
| denote EV at ISO 100. However, this term does not derive from a standards
| |
| body, and has had several conflicting definitions.
| |
| | |
| ==Relationship of EV to lighting conditions==
| |
| | |
| The recommended <var>f</var>-number and exposure time for given lighting conditions
| |
| and ISO speed are given by the exposure equation
| |
| | |
| :<math>
| |
| \frac {N^2} {t} = \frac {L \cdot S} {K} \,,
| |
| </math>
| |
| | |
| where<ref>
| |
| Symbols for the quantities in the exposure equation have varied over time;
| |
| the symbols used in this article reflect current practice for many authors,
| |
| such as [[#CITEREFRay2000|Ray (2000)]].
| |
| </ref>
| |
| | |
| * ''N'' is the relative [[aperture]] ([[f-number]])
| |
| * ''t'' is the exposure time (“[[shutter speed]]”) in seconds<ref name="no_units">
| |
| In a mathematical expression involving physical quantities, it is common practice to require that the argument to a [[transcendental function]] (such as the [[logarithm]]) be [[dimensionless]]. The definition of EV ignores the units in the denominator and uses only the [[ISO 31-0#Quantities and units|numerical value]] of the exposure time in seconds; EV is not the expression of a physical law, but simply a number for encoding combinations of camera settings.
| |
| </ref>
| |
| * ''L'' is the average scene [[luminance]]
| |
| * ''S'' is the ISO arithmetic [[film speed|speed]]
| |
| * ''K'' is the reflected-light [[Light meter#Calibration constants|meter calibration constant]]
| |
| | |
| Applied to the right-hand side of the exposure equation, exposure value is
| |
| | |
| :<math>\mathrm {EV} = \log_2 {\frac {L \cdot S} {K} } \,.</math>
| |
| | |
| Camera settings also can be determined from incident-light measurements,
| |
| for which the exposure equation is
| |
| | |
| :<math>
| |
| \frac {N^2} {t} = \frac {E \cdot S} {C} \,,
| |
| </math>
| |
| | |
| where
| |
| | |
| * ''E'' is the [[illuminance]]
| |
| * ''C'' is the incident-light meter calibration constant
| |
| | |
| In terms of exposure value, the right-hand side becomes
| |
| | |
| :<math>\mathrm {EV} = \log_2 {\frac {E \cdot S} {C} } \,.</math>
| |
| | |
| 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 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),
| |
| a greater EV corresponds to greater luminance or illuminance. | |
| | |
| ==EV and APEX==
| |
| | |
| {{Main|APEX system}}
| |
| | |
| The ''Additive system of Photographic EXposure'' ([[APEX system|APEX]])
| |
| proposed in the 1960 [[American Standards Association|ASA]] standard
| |
| for monochrome film speed, [[#CITEREFASA PH2.5-1960|ASA PH2.5-1960]],
| |
| extended the concept of exposure value to all quantities in the
| |
| exposure equation by taking base-2 logarithms, reducing application of the
| |
| equation to simple addition and subtraction. In terms of exposure value,
| |
| the left-hand side of the exposure equation became | |
| | |
| :<math>E_v = A_v + T_v \,,</math>
| |
| | |
| where <var>A<sub>v</sub></var> (aperture value) and <var>T<sub>v</sub></var> (time value) were defined as:
| |
| | |
| :<math>A_v = \log_2</math> <math>A^2</math>
| |
| | |
| and
| |
| | |
| :<math>T_v = \log_2</math> <math>(1/T) \,,</math>
| |
| | |
| with
| |
| | |
| * <var>A</var> the relative aperture (f-number)
| |
| * <var>T</var> the exposure time (“shutter speed”) in seconds<ref name="no_units"/>
| |
| | |
| <var>A<sub>v</sub></var> and <var>T<sub>v</sub></var> represent the numbers of stops from {{F/}}1 and 1 second, respectively.
| |
| | |
| Use of APEX required logarithmic markings on aperture and shutter controls,
| |
| however, and these never were incorporated in consumer cameras. With the
| |
| inclusion of built-in exposure meters in most cameras shortly after APEX
| |
| was proposed, the need to use the exposure equation was eliminated, and
| |
| APEX saw little actual use.
| |
| | |
| Though it remains of little interest to the end user, APEX has seen a partial resurrection in the [[Exif]] standard, which calls for storing exposure data using APEX values. See [[APEX_system#Use_of_APEX_values_in_Exif|Use of APEX values in Exif]] for additional discussion.
| |
| | |
| ==EV as a measure of luminance and illuminance==
| |
| | |
| For a given ISO speed and meter calibration constant, there is a direct relationship
| |
| between exposure value and luminance (or illuminance). Strictly, EV is not a measure of
| |
| luminance or illuminance; rather, an EV
| |
| corresponds to a luminance (or illuminance) for which a camera with a given
| |
| ISO speed would use the indicated EV to obtain the nominally correct
| |
| exposure. Nonetheless, it is common practice among photographic equipment
| |
| manufacturers to express luminance in EV for ISO 100 speed, as when
| |
| specifying metering range ([[#CITEREFRay2000|Ray 2000]], 318) or autofocus sensitivity. And the practice is
| |
| long established;
| |
| [[#CITEREFRay2002|Ray (2002)]], 592) cites [[#CITEREFUlffers1968|Ulffers (1968)]]
| |
| as an early example. Properly, the meter calibration constant as well as the
| |
| ISO speed should be stated, but this seldom is done.
| |
| | |
| Values for the reflected-light calibration constant <var>K</var> vary slightly among manufacturers; a common choice is 12.5 ([[Canon Inc.|Canon]], [[Nikon]], and [[Mamiya|Sekonic]]<ref>Specifications for Sekonic light meters are available on the [http://www.sekonic.com/ Sekonic] web site under "Products".</ref>).
| |
| Using {{nowrap|1=<var>K</var> = 12.5}}, the relationship between EV at ISO 100 and luminance <var>L</var> is then
| |
| | |
| :<math>L = 2^{\mathrm {EV} - 3} \,.</math>
| |
| | |
| Values of luminance at various values of EV based on this relationship are
| |
| shown in Table 3. Using this relationship, a reflected-light exposure meter
| |
| that indicates in EV can be used to determine luminance. | |
| | |
| As with luminance, common practice among photographic
| |
| equipment manufacturers is to express illuminance in EV for ISO 100 speed
| |
| when specifying metering range.<ref>The metering range for an
| |
| incident-light meter specified in EV at ISO 100 usually applies to a
| |
| hemispherical sensor, so strictly speaking, it does not directly relate to
| |
| illuminance.</ref>
| |
| | |
| The situation with incident-light meters is more
| |
| complicated than that for reflected-light meters, because the calibration
| |
| constant <var>C</var> depends on the sensor type. Two sensor types are common: flat
| |
| ([[cosine]]-responding) and hemispherical ([[cardioid]]-responding).
| |
| Illuminance is measured with a flat sensor; a typical value for
| |
| <var>C</var> is 250 with illuminance in [[lux]]. Using {{nowrap|1=<var>C</var> = 250}},
| |
| the relationship between EV at ISO 100 and illuminance <var>E</var> is then | |
| | |
| :<math>E = 2.5 \times 2^{\mathrm {EV}} \,.</math>
| |
| | |
| Values of illuminance at various values of EV based on this relationship are
| |
| shown in Table 3. Using this relationship, an incident-light exposure meter
| |
| that indicates in EV can be used to determine illuminance. | |
| | |
| Although illuminance measurements may indicate appropriate exposure for a
| |
| flat subject, they are less useful for a typical scene in which many
| |
| elements are not flat and are at various orientations to the camera. For
| |
| determining practical photographic exposure, a hemispherical sensor has
| |
| proven more effective. With a hemispherical sensor, typical values for
| |
| <var>C</var> are between 320 (Minolta) and 340 (Sekonic) with illuminance
| |
| in lux. If illuminance is interpreted loosely, measurements with a
| |
| hemispherical sensor indicate “scene illuminance”.
| |
| | |
| [[Light meter#Exposure meter calibration|Exposure meter calibration]] is
| |
| discussed in detail in the [[Light meter]] article.
| |
| | |
| : '''Table 3. Exposure value vs. luminance (ISO 100, <var>K</var> = 12.5) and illuminance (ISO 100, <var>C</var> = 250)'''
| |
| :{| class="wikitable" style="text-align: center"
| |
| |-
| |
| ! rowspan="2" | EV<sub>100</sub>
| |
| ! colspan="2" | Luminance
| |
| ! colspan="2" | Illuminance
| |
| |-
| |
| ! [[Candela per square metre|cd/m<sup>2</sup>]]
| |
| ! [[Footlambert|fL]]
| |
| ! [[Lux|lx]]
| |
| ! [[Foot-candle|fc]]
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | −4 || 0.008 || 0.0023 || 0.156 || 0.015
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | −3 || 0.016 || 0.0046 || 0.313 || 0.029
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | −2 || 0.031 || 0.0091 || 0.625 || 0.058
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | −1 || 0.063 || 0.018 || 1.25 || 0.116
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 0 || 0.125 || 0.036 || 2.5 || 0.232
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 1 || 0.25 || 0.073 || 5 || 0.465
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 2 || 0.5 || 0.146 || 10 || 0.929
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 3 || 1 || 0.292 || 20 || 1.86
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 4 || 2 || 0.584 || 40 || 3.72
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 5 || 4 || 1.17 || 80 || 7.43
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 6 || 8 || 2.33 || 160 || 14.9
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 7 || 16 || 4.67 || 320 || 29.7
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 8 || 32 || 9.34 || 640 || 59.5
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 9 || 64 || 18.7 || 1280 || 119
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 10 || 128 || 37.4 || 2560 || 238
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 11 || 256 || 74.7 || 5120 || 476
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 12 || 512 || 149 || 10,240 || 951
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 13 || 1024 || 299 || 20,480 || 1903
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 14 || 2048 || 598 || 40,960 || 3805
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 15 || 4096 || 1195 || 81,920 || 7611
| |
| |-
| |
| | style="text-align: right; padding: 0.1em 0.5em;" | 16 || 8192 || 2391 || 163,840 || 15,221
| |
| |}
| |
| | |
| ==Notes==
| |
| | |
| <references />
| |
| | |
| ==See also==
| |
| {{Portal|Photography}}
| |
| | |
| * [[APEX system]]
| |
| * [[Exposure compensation]]
| |
| * [[Light meter#Exposure meter calibration|Exposure meter calibration]]
| |
| * [[High dynamic range imaging]]
| |
| | |
| ==References==
| |
| | |
| * <cite id="CITEREFAdams1981">Adams, Ansel. 1981. ''The Negative.'' Boston: New York Graphic Society.</cite> ISBN 0-8212-1131-5
| |
| * <cite id="CITEREFANSI PH2.7-1973">ANSI PH2.7-1973. ''American National Standard Photographic Exposure Guide''. New York: American National Standards Institute.</cite> Superseded by ANSI PH2.7-1986
| |
| * <cite id="CITEREFANSI PH2.7-1986">ANSI PH2.7-1986. ''American National Standard for Photography — Photographic Exposure Guide''. New York: American National Standards Institute.</cite>
| |
| * <cite id="CITEREFASA PH2.5-1960">ASA PH2.5-1960. ''American Standard Method for Determining Speed of photographic Negative Materials (Monochrome, Continuous Tone)''. New York: United States of America Standards Institute.</cite>
| |
| * <cite id="CITEREFASA PH2.15-1964">ASA PH2.15-1964 (R1976). American Standard: Automatic Exposure Controls for Cameras. New York: United States of America Standards Institute.</cite>
| |
| * <cite id="CITEREFCanonWWW">{{cite web |url = http://cpn.canon-europe.com/content/education/infobank/camera_settings/shooting_modes.do |title = Canon Professional Network – Shooting modes |accessdate= 23 July 2013}}</cite>
| |
| * <cite id="CITEREFDavis1999">Davis, Phil. 1999. '' [http://books.elsevier.com/us/focalbooks/us/subindex.asp?isbn=0240803434 Beyond the Zone System]'', 4th ed. Boston: Focal Press.</cite> ISBN 0-240-80343-4
| |
| * <cite id="CITEREFJonesCondit1941">[[Loyd Ancile Jones|Jones, Loyd Ancile]], and H. R. Condit. 1941. The Brightness Scale of Exterior Scenes and the Computation of Correct Photographic Exposure. ''Journal of the Optical Society of America'' 31:11, Nov. 1941, 651–678.</cite>
| |
| * <cite id="CITEREFJonesCondit1948">[[Loyd Ancile Jones|Jones, Loyd Ancile]], and H. R. Condit. 1948. Sunlight and skylight as determinants of Photographic exposure. I. Luminous density as determined by solar altitude and atmospheric conditions. ''Journal of the Optical Society of America'' 38:2, Feb. 1948, 123–178.</cite>
| |
| * <cite id="CITEREFJonesCondit1949">[[Loyd Ancile Jones|Jones, Loyd Ancile]], and H. R. Condit. 1949. Sunlight and skylight as determinants of Photographic exposure. II. Scene structure, directional index, photographic efficiency of daylight, safety factors, and evaluation of camera exposure. ''Journal of the Optical Society of America'' 39:2, Feb. 1949, 94–135.</cite>
| |
| * <cite id="CITEREFRay2000">Ray, Sidney F. 2000. Camera Exposure Determination. In ''The Manual of Photography: Photographic and Digital Imaging'', 9th ed. Ed. Ralph E. Jacobson, Sidney F. Ray, Geoffrey G. Atteridge, and Norman R. Axford. Oxford: Focal Press.</cite> ISBN 0-240-51574-9
| |
| * <cite id="CITEREFRay2002">Ray, Sidney F. 2002. [http://books.elsevier.com/us/focalbooks/us/subindex.asp?isbn=0240515404 ''Applied Photographic Optics'']. 3rd ed. Oxford: Focal Press.</cite> ISBN 0-240-51540-4
| |
| * <cite id="CITEREFUlffers1968">Ulffers, D. 1968. Sensitivity Specifications of Exposure Meters. ''British Journal of Photography'' 115, 47.
| |
| | |
| ==Further reading==
| |
| | |
| * Eastman Kodak Company. ''Existing-Light Photography'', 3rd ed. Rochester, NY: Silver Pixel Press, 1996. ISBN 0-87985-744-7
| |
| | |
| ==External links==
| |
| | |
| * Doug Kerr’s [http://doug.kerr.home.att.net/pumpkin/APEX.pdf The Additive System for Photographic Exposure] ([[PDF]])
| |
| * Fred Parker’s [http://www.fredparker.com/ultexp1.htm#Light%20Intensity%20Chart table of exposure values] for various lighting situations
| |
| | |
| {{Photography}}
| |
| [[Category:Science of photography]]
| |
| [[Category:Photometry]]
| |
| [[Category:Units of illuminance]]
| |