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Exposure (photography)

Exposure (photography)

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In photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...

, exposure is the total amount of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 allowed to fall on the photographic medium (photographic film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...

 or image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...

) during the process of taking a photograph
Photograph
A photograph is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic imager such as a CCD or a CMOS chip. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of...

. Exposure is measured in lux
Lux
The lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface...

 second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

s, and can be computed from exposure value
Exposure value
In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

 (EV) and scene luminance
Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square...

 over a specified area.

In photographic jargon, an exposure generally refers to a single shutter cycle. For example: a long exposure refers to a single, protracted shutter cycle to capture enough low-intensity light, whereas a multiple exposure
Multiple exposure
In photography, a multiple exposure is the superimposition of two or more individual exposures to create a single photograph. The exposure values may or may not be identical to each other.-Overview:...

 involves a series of relatively brief shutter cycles; effectively layering a series of photographs in one image. For the same film speed
Film speed
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system....

, the accumulated photometric exposure (Hv) should be similar in both cases.

Photometric and radiometric exposure


Photometric
Photometry (optics)
Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy in terms of absolute power; rather, in photometry, the radiant power at each wavelength is weighted by...

 or luminous exposure Hv is the accumulated physical quantity of visible light energy (weighted by the luminosity function
Luminosity function
The luminosity function or luminous efficiency function describes the average visual sensitivity of the human eye to light of different wavelengths. It should not be considered perfectly accurate in every case, but it is a very good representation of visual sensitivity of the human eye and it is...

) applied to a surface during a given exposure time. It is defined as:


where
  • Hv is the luminous exposure (usually in lux seconds)
  • Ev is the image-plane illuminance
    Illuminance
    In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per...

     (usually in lux
    Lux
    The lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface...

    )
  • t is the exposure time (in second
    Second
    The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

    s)


The radiometric
Radiometry
In optics, radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye...

 quantity radiant exposure He is sometimes used instead; it is the product of image-plane irradiance
Irradiance
Irradiance is the power of electromagnetic radiation per unit area incident on a surface. Radiant emittance or radiant exitance is the power per unit area radiated by a surface. The SI units for all of these quantities are watts per square meter , while the cgs units are ergs per square centimeter...

 Ee and time, the accumulated amount of incident "light" energy per area:


where
  • He is the radiant exposure (usually in joule
    Joule
    The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...

    s per square metre
    Square metre
    The square metre or square meter is the SI derived unit of area, with symbol m2 . It is defined as the area of a square whose sides measure exactly one metre...

     (J/m2))
  • Ee is the irradiance
    Irradiance
    Irradiance is the power of electromagnetic radiation per unit area incident on a surface. Radiant emittance or radiant exitance is the power per unit area radiated by a surface. The SI units for all of these quantities are watts per square meter , while the cgs units are ergs per square centimeter...

     (usually in watt
    Watt
    The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...

    s per square metre (W/m2))
  • t is the exposure time (in second
    Second
    The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

    s)


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
Spectral sensitivity
Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal....

, the exposure is still measured in radiometric units (joules per square meter), rather than photometric units (weighted by 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
UV filter
UV filters are individual compounds or mixtures to prevent ultraviolet light from getting through. UV filters are used in sunscreens to protect skin or in photography to reduce the level of ultraviolet light that strikes the recording medium....

 and IR filter), or a benefit (see infrared photography
Infrared photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about...

 and full-spectrum photography). The use of radiometric units is appropriate to characterize such sensitivity to invisible light.

In sensitometric data, such as characteristic curves, the log exposure is conventionally expressed as log10(H). Photographers more familiar with base-2 logarithmic scales (such as exposure value
Exposure value
In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

s) can convert using .

Optimum exposure


"Correct" exposure may be defined as an exposure that achieves the effect the photographer intended.

A more technical approach recognises that a photographic film (or sensor) has a physically limited useful exposure range
Sensitometry
Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield with early black-and-white emulsions...

, sometimes called its dynamic range
Dynamic range
Dynamic range, abbreviated DR or DNR, is the ratio between the largest and smallest possible values of a changeable quantity, such as in sound and light. It is measured as a ratio, or as a base-10 or base-2 logarithmic value.-Dynamic range and human perception:The human senses of sight and...

. 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 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
Sensitometry
Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield with early black-and-white emulsions...

. This ensures that no 'significant' information is lost during capture.

It is worth noting that 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
Film noir
Film noir is a cinematic term used primarily to describe stylish Hollywood crime dramas, particularly those that emphasize cynical attitudes and sexual motivations. Hollywood's classic film noir period is generally regarded as extending from the early 1940s to the late 1950s...

. However, it is technically much easier to discard recorded information during post processing
Image processing
In electrical engineering and computer science, image processing is any form of signal processing for which the input is an image, such as a photograph or video frame; the output of image processing may be either an image or, a set of characteristics or parameters related to the image...

 than to try to 're-create' unrecorded information.

In 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 the useful exposure range at the same time. Methods for dealing with this situation include: using some kind of fill light
Fill light
In television, film, stage, or photographic lighting, a fill light may be used to reduce the contrast of a scene and provide some illumination for the areas of the image that are in shadow...

ing to gently increase the illumination in shadow areas; using a graduated ND filter or gobo
Gobo (lighting)
A gobo derived from "Go Between" or Goes Before Optics -originally used on film sets, is a physical template slotted inside, or placed in front of, a lighting source, used to control the shape of emitted light....

 to reduce the amount of light coming from the highlight areas; or varying the exposure between multiple, otherwise identical, photographs (exposure bracketing) and then combining them afterwards in some kind of HDRI process.

Overexposure and underexposure


A photograph may be described as overexposed when it has 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
Clipping (photography)
In digital photography and digital video, clipping is a result of capturing or processing an image where the intensity in a certain area falls outside the minimum and maximum intensity which can be represented. It is an instance of signal clipping in the image domain...

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

Manual exposure


In manual mode, the photographer adjusts the lens aperture and/or shutter speed
Shutter speed
In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....

 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
Depth of field
In optics, particularly as it relates to film and photography, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image...

, and a slower shutter increases exposure but also increases the opportunity for motion blur
Motion blur
Motion blur is the apparent streaking of rapidly moving objects in a still image or a sequence of images such as a movie or animation. It results when the image being recorded changes during the recording of a single frame, either due to rapid movement or long exposure.- Photography :When a camera...

.

'Manual' exposure calculations may be based on some method of light meter
Light meter
A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph...

ing with a working knowledge of exposure value
Exposure value
In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

s, the APEX system
APEX system
APEX stands for Additive system of Photographic EXposure, whichwas proposed in the 1960 ASA standardfor monochrome film speed, ASA PH2.5-1960,as a means of simplifying exposure computation.-Exposure equation:...

 and/or the Zone System
Zone system
The Zone System is a photographic technique for determining optimal film exposure and development, formulated by Ansel Adams and Fred Archer. Adams described how the Zone System was developed: "I take this opportunity to restate that the Zone System is not an invention of mine; it is a codification...

.

Automatic exposure


A camera in automatic exposure (abbreviation: 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
Through-the-lens metering
Through-the-lens metering is a photographic term describing a feature of cameras capable of measuring light levels in a scene through their taking lenses, as opposed to a separate metering window...

 exposure meter
Light meter
A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph...

.

Aperture priority
Aperture priority
Aperture priority, often abbreviated A or Av on a camera mode dial, is a setting on some cameras that allows the user to choose a specific aperture value while the camera selects a shutter speed to match. The camera will ensure proper exposure...

 mode (commonly abbreviated to Av) gives 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
Shutter priority
Shutter priority refers to a setting on some cameras that allows the user to choose a specific shutter speed while the camera adjusts the aperture to ensure correct exposure...

 mode (commonly abbreviated to Tv) gives manual shutter control, with automatic aperture compensation. In each case, the actual exposure level is still determined by the camera's exposure meter.

Exposure compensation


The purpose of an exposure meter is to estimate the subject's mid-tone luminance
Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square...

 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 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 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.

Exposure control


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
Film speed
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system....

 and is measured on a scale published by the International Organization for Standardization
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

 (ISO). Faster film, that is, film with a higher ISO rating, requires less exposure to make a good image. Digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...

s usually have variable ISO settings that provide additional flexibility. Exposure is a combination of the length of time and the illuminance
Illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per...

 at the photosensitive material. Exposure time is controlled in a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

 by shutter speed
Shutter speed
In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....

 and the illuminance by the lens aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...

 and the scene luminance
Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square...

. Slower shutter speeds (exposing the medium for a longer period of time), and 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 and a shutter speed of 1/100 of a second. This is called the sunny 16 rule
Sunny 16 rule
In photography, the Sunny 16 rule is a method of estimating correct daylight exposures without a light meter. Apart from the obvious advantage of independence from a light meter, the Sunny 16 rule can also aid in achieving correct exposure of difficult subjects...

: at an aperture of 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.

Reciprocity


An important principle of exposure is reciprocity
Reciprocity (photography)
In photography reciprocity refers to the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be determined by the...

. If one exposes the film or sensor for a longer period, 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 (to obtain a shallow depth of field). As is 3 stops "faster" than , with each stop meaning double the amount of light, a new shutter speed of (1/125)/(2·2·2) = 1/1000 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
Sensitometry
Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield with early black-and-white emulsions...

) but it is close enough over the exposure range of about one second to 1/1000 of a second. Outside of this range, it becomes necessary to increase the exposure from 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
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...

 image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...

s can also be subject to a form of reciprocity failure.

Determining exposure


The Zone System
Zone system
The Zone System is a photographic technique for determining optimal film exposure and development, formulated by Ansel Adams and Fred Archer. Adams described how the Zone System was developed: "I take this opportunity to restate that the Zone System is not an invention of mine; it is a codification...

 is another method of determining exposure and development combinations to achieve 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
High dynamic range imaging
In image processing, computer graphics, and photography, high dynamic range imaging is a set of techniques that allows a greater dynamic range between the lightest and darkest areas of an image than current standard digital imaging techniques or photographic methods...

) by combining several different exposures (varying only the shutter speeds) made in quick succession.

Today, most cameras automatically determine the correct exposure at the time of taking a photograph by using a built-in light meter
Light meter
A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph...

, or multiple point meters interpreted by a built-in computer, see metering mode
Metering mode
In photography, the metering mode refers to the way in which a camera determines the exposure.- Examples of metering modes :Cameras generally allow the user to select between spot, center-weighted average, or multi-zone metering modes....

.

Negative/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


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 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.

Highlights



Areas of 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 ameliorate 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 is usually somewhat recoverable when printing or transferring to digital.

A loss of highlights in a photograph is usually undesirable, but in some cases can be considered to "enhance" appeal. Examples include black-and-white photography and portraits with an out-of-focus background.

Blacks


Areas of a photo where information is lost due to extreme darkness are described as "crushed blacks". Digital capture tends to be more tolerant of underexposure, allowing better recovery of shadow detail, than same-ISO negative print film.

Crushed blacks cause loss of detail, but can be used for artistic effect.

See also

  • Exposure bracketing
  • Shutter speed
    Shutter speed
    In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....

     (also called exposure time)
  • Film speed
    Film speed
    Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system....

  • Exposure value
    Exposure value
    In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

  • Gray card
    Gray card
    A gray card is a middle gray reference, typically used together with a reflective light meter, as a way to produce consistent image exposure and/or color in film and photography....

  • Light value
    Light value
    In photography, light value has been used to refer to a“light level” for either incident or reflected light, often on a base-2 logarithmic scale.The term does not derive from a published standard, and has had severaldifferent meanings:...

  • Multiple exposure
    Multiple exposure
    In photography, a multiple exposure is the superimposition of two or more individual exposures to create a single photograph. The exposure values may or may not be identical to each other.-Overview:...

  • Sensitometry
    Sensitometry
    Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield with early black-and-white emulsions...

     (and Hurter–Driffield curves)
  • Night photography
    Night photography
    Night photography refers to photographs taken outdoors between dusk and dawn. Night photographers generally have a choice between using artificial light and using a long exposure, exposing the scene for seconds, minutes, and even hours in order to give the film or digital sensor enough time to...

  • Long exposure multiple flash photographic technique
  • Bulb (photography)
    Bulb (photography)
    Bulb, abbreviated B, is a shutter speed setting on an adjustable camera that allows for long exposure times under the direct control of the photographer. With this setting, the shutter simply stays open as long as the shutter release button remains depressed...

  • Light painting
    Light Painting
    Light painting, also known as light drawing or light graffiti is a photographic technique in which exposures are made usually at night or in a darkened room by moving a hand-held light source or by moving the camera. In many cases the light source itself does not have to appear in the image...

  • High dynamic range imaging
    High dynamic range imaging
    In image processing, computer graphics, and photography, high dynamic range imaging is a set of techniques that allows a greater dynamic range between the lightest and darkest areas of an image than current standard digital imaging techniques or photographic methods...

  • Zebra patterning
    Zebra patterning
    Zebra patterning is a feature found on some prosumer and most professional video cameras to aid in correct exposure. When enabled, areas of the image over a certain threshold are filled with a striped or cross-hatch pattern. Often, two thresholds are available: 70% and 100%...