RAW image format
Encyclopedia
A camera raw image file contains minimally processed data from the image sensor
of either a digital camera
, image scanner
, or motion picture film scanner
. Raw files are so named because they are not yet processed and therefore are not ready to be printed
or edited with a bitmap graphics editor. Normally, the image is processed by a raw converter in a wide-gamut
internal colorspace where precise adjustments can be made before conversion to a "positive" file format such as TIFF or JPEG
for storage, printing, or further manipulation, which often encodes the image in a device-dependent colorspace. These images are often described as "RAW image files", although there is not actually one single raw file format. In fact there are dozens if not hundreds of such formats in use by different models of digital equipment (like cameras or film scanners).
Raw image files are sometimes called digital negatives, as they fulfill the same role as negatives
in film photography: that is, the negative is not directly usable as an image, but has all of the information needed to create an image. Likewise, the process of converting a raw image file into a viewable format is sometimes called developing a raw image, by analogy with the film development process used to convert photographic film
into viewable prints. The selection of the final choice of image rendering is part of the process of white balancing and color grading
.
Like a photographic negative, a raw digital image may have a wider dynamic range or color gamut
than the eventual final image format, and it preserves most of the information of the captured image. The purpose of raw image formats is to save, with minimum loss of information, data obtained from the sensor, and the conditions surrounding the capturing of the image (the metadata
).
Most raw image file formats store information sensed according to the geometry of the sensor's individual photo-receptive elements (sometimes called pixels) rather than points in the expected final image: sensors with hexagonal element displacement, for example, record information for each of their hexagonally-displaced cells, which a decoding software will eventually transform into the rectangular geometry during "digital developing".
, often follows a common pattern, that is:
Many raw file formats (including 3FR (Hasselblad
), DCR, K25, KDC (Kodak), IIQ (Phase One), CR2 (Canon), ERF (Epson), MEF (Mamiya
), MOS (Leaf
), NEF (Nikon), ORF
(Olympus
), PEF (Pentax
), RW2 (Panasonic
) and ARW, SRF, SR2 (Sony
)) are based on the TIFF file format. These files may deviate from the TIFF standard in a number of ways, including the use of a non-standard file header, the inclusion of additional image tags and the encryption of some of the tagged data.
Panasonic's raw converter corrects geometric distortion and chromatic aberration
on such cameras as the LX3
, with necessary correction information presumably included in the raw.. Phase One (company)'s raw converter Capture One
also offers corrections for geometrical distortion, chromatic aberration
, purple fringing and keystone correction emulating tilt-shift in software, on most raw files from over 100 different cameras . The same holds for Canon's DPP application, at least for all more expensive cameras like all SLRs and the G series of compact cameras.
DNG
, the Adobe digital negative
format, is an extension of the TIFF 6.0 format and is compatible with TIFF/EP
, and uses various open format
s and/or standards
, including Exif metadata
, XMP metadata
, IPTC metadata
, CIE XYZ coordinates
, ICC profile
s, and JPEG
.
, the raw file plays the role that photographic film
plays in film photography
. Raw files thus contain the full resolution (typically 12- or 14-bit) data as read out from each of the camera's image sensor
pixel
s.
The camera's sensor is almost invariably overlaid with a color filter array
, usually a Bayer filter
, consisting of a mosaic of a 2x2 matrix of red, green, blue and (second) green filters.
One variation on the Bayer filter is the RGBE filter
of the Sony Cyber-shot
DSC-F828, which exchanged the green in the RG rows with "emerald"
(a blue-green
or cyan
color). Other sensors, such as the Foveon X3 sensor
, capture information directly in RGB form, having three pixel sensors
in each location, one for each color component; these camera RGB raw data still need to be processed to make an image file, as the RGB values correspond to the responses of the sensors, not to a standard color space like sRGB, though they do not need to be demosaiced
.
Flatbed
and film scanner
sensors are typically straight narrow RGB or RGBI (where "I" is intensity) strips that are swept across an image. The HDRi raw data format
is able to store the infrared raw data, which can be used for infrared cleaning
, as an additional 16-bit channel. The remainder of the discussion about raw files applies to them as well. (Some scanners do not allow the host system access to the raw data at all, as a speed compromise. The raw data are processed very rapidly inside the scanner to select out the best part of the available dynamic range so only the result is passed to the computer for permanent storage, reducing the amount of data transferred and therefore the bandwidth requirement for any given speed of image throughput.)
To obtain an image from a raw file, this mosaic of data must be converted into standard RGB form. This is often referred to as "raw development".
When converting from the four sensor 2x2 Bayer matrix raw form into single RGB pixels the original 4x12 (or 14) bit data is converted to 4x3x8 bit. The green pair is used to control the overall luminance of the processed output pixel (since the human eye is more sensitive to it - and so green is used as the dominant channel for in-camera black-and-white
conversions).
If raw format data is available, it can be used in high dynamic range imaging
conversion (instead of the "standard" HDI approach of exposing three separate images, one under exposed, one correct and one over-exposed, and "overlaying" one on top of the other).
into a JPEG file using settings for white balance, colour saturation, contrast
, and sharpness
that are either selected automatically or entered by the photographer before taking the picture. Cameras that produce raw files save these settings in the file, but defer the processing. This results in an extra step for the photographer, so raw is normally only used when additional computer processing is intended. However, raw has numerous advantages over JPEG such as:
for conversion of their raw image data into standard RGB images. Other processing and conversion programs
and plugins are available from vendors that have either licensed the technology from the camera manufacturer or reverse-engineered
the particular raw format and provided their own processing algorithms.
Adobe Photoshop
contains extensive support of raw formats since version CS2, as does Adobe Photoshop Lightroom.
Capture One
supports a vast range of raw image files from both DSLRs (Canon, Nikon, Panasonic, Sony etc.) and medium-format cameras (Phase One
, Leaf, Mamiya etc.) .
Paint Shop Pro likewise contains RAW support, although as in the case of most editors updates to the program may be necessary to attain compatibility with newer RAW formats as they are released.
Picasa
is a free basic editor and organizer that supports most RAW files. IrfanView
similarly is a freeware/shareware basic editor with support for most RAW files.
Microsoft's Digital Image 2006 recognizes and organizes raw image formats such as .crw, .cr2, and .nef, which are file formats produced by Canon and Nikon, but that product was discontinued in 2007.
Microsoft supplies free software for Windows XP
to integrate viewing and printing into the system's other photo tools; however, this software was last updated in 2005 and does not support many raw files from cameras released subsequently.
The Windows Camera Codec pack allows native viewing of RAW format files from 120 digital SLR cameras from multiple manufacturers in Windows Explorer and Windows Live Photo Gallery, in Windows Vista
and Windows 7.
Windows XP and Vista both support the WIC
codec standard. Products such as Konvertor, Windows Photo Gallery
, Windows Live Photo Gallery
and FastPictureViewer Professional
can view raw formats for which the necessary WIC
codecs are installed. Camera manufacturers Canon, Nikon
, Sony
, Olympus
and Pentax
have released WIC codecs, although some manufactures are only providing codec support for the 32-bit versions of Vista. A commercial DNG
codec is also available from Ardfry Imaging, while the makers of FastPictureViewer have released a WIC codec pack, adding support for 22 raw formats to Windows in both 32-bit and 64-bit versions, as donationware
.
In 2005, Apple Computer introduced several products which offered raw file support. In January, Apple released iPhoto
5, which offered basic support for viewing and editing many raw file formats. In April of that year, Apple introduced a new version of its operating system, Mac OS X v10.4, which added raw support directly to the operating system, as part of the ImageIO framework, which adds raw support automatically to the majority of Mac OS X applications both from Apple (such as Preview, Mac OS X's PDF and image viewing application and Aperture, a photo post-production software package for professionals) as well as all third party applications which make use of the ImageIO frameworks. Semi-regular updates to OS X generally include updated support for new raw file formats introduced in the intervening months by camera makers.
There are many other "raw workflow applications" designed to provide efficient processing and post-processing of raw images, including Helicon Filter
, DxO Labs
' DxO Optics Pro, Hasselblad
's Phocus and Bibble Labs' Bibble Pro
. Like Apple Aperture, Adobe Photoshop
and Lightroom, LaserSoft Imaging's SilverFast
, and PhotoLine, these programs provide sophisticated controls for processing the information stored in the raw file and converting raw files to JPEG or TIFF. Picasa
, a free image editing and cataloguing program from Google
, can read and display many raw formats, but like iPhoto, Picasa provides only limited tools for processing the data in a raw file.
Light Crafts' LightZone
photo editing software provides the ability to edit many raw formats natively. Most tools are raw converters, but LightZone allows a user to edit a raw file as if it were TIFF or JPEG.
program, dcraw
, supports most raw formats and can be made to run on operating systems not supported by most commercial software (such as Unix
). Libraw is an API library based on dcraw, offering a more convenient interface for reading and converting raw files. HDR PhotoStudio
and AZImage are some of the commercial applications that use Libraw. Jrawio is another API library, written in pure Java code and compliant to the standard Java Image I/O API.
Darktable is an open source
RAW workflow tool for Linux and other open unix-like operating systems. Features native 32-bit floating point processing in Lab color space
and plugin architecture.
ExifTool
supports the reading, writing and editing of metadata in raw image files. ExifTool supports many different types of metadata including Exif, GPS, IPTC
, XMP
, JFIF
, GeoTIFF
, ICC Profile
, Photoshop IRB, FlashPix
, AFCP and ID3, as well as the maker notes of many digital cameras.
The latest version of GIMP
, a free open source photo editing package, imports many raw formats. Older versions have a plug-in which allows it to read and convert raw files.
ImageMagick
, a popular free software suit for image manipulation and conversion, reads many different raw file formats. ImageMagick
is available for Linux/Unix, Mac OS, Windows and other platforms.
Photivo is an open source
raw processor with a non-destructive 16-bit processing pipeline aimed at flexibility. It runs on Linux, Mac OSX and Windows and integrates tightly with GIMP
.
Rawstudio
is another open source
program to read and manipulate images from digital cameras. The main focus is on the streamlined interface to allow for fast review and processing of large image collections.
RawTherapee is an open source
raw converter supporting the Linux, Mac OS and Windows operating systems.
UFRaw
is free software based on dcraw. It can be used as a GIMP
plugin and is available for most operating systems.
, Canon and Sony
, encrypt
portions of the file in an attempt to prevent third-party tools from accessing them.
This industry-wide situation of inconsistent formatting has concerned many photographers who worry that their valuable raw photos may someday become inaccessible, as computer operating systems and software programs become obsolete and abandoned raw formats are dropped from new software. The availability of high-quality open source
software which decodes raw image formats, particularly dcraw
, has helped to alleviate these concerns. An essay by Michael Reichmann and Juergen Specht stated "here are two solutions – the adoption by the camera industry of A: Public documentation of RAW formats; past, present and future, or, more likely B: Adoption of a universal RAW format"; and included in its petition "I am also requesting that your company adopt a universal RAW format. The DNG format has been put forward as such a possible standard, but we are willing to accept any truly open standard as the industry may agree upon". "Planning for [US] Library of Congress Collections" identifies RAW file formats as "less desirable file formats", and identifies DNG
as a suggested alternative.
DNG
is the only raw image format for which industry-wide buy-in is being sought. It is based upon, and compatible with, the ISO standard raw image format ISO 12234-2, TIFF/EP
, and is being used by ISO in their revision of that standard. (See the Standardization section, below.)
The ISO standard raw image format is ISO 12234-2, better known as TIFF/EP
. (TIFF/EP also supports "non-raw", or "processed", images). TIFF/EP provided a basis for the raw image formats of a number of cameras. For example, Nikon
's NEF raw files are based on TIFF/EP, and include a tag which identifies the version of TIFF/EP they are based on. Adobe's DNG (Digital Negative)
raw file format was based on TIFF/EP, and the DNG specification states "DNG ... is compatible with the TIFF-EP standard". Several cameras use DNG as their raw image format, so in that limited sense they use TIFF/EP too.
Adobe Systems
launched this DNG
raw image format in September 2004. By September 2006, several camera manufacturers had started to announce support for DNG in newer camera models, including Leica, Samsung
, Ricoh
, Pentax
, Hasselblad
(native camera support); and, Better Light
(export). The Leica Digital-Modul-R (DMR) was first to use DNG as its native format. In September 2009 Adobe stated that there were no known intellectual property encumbrances or license requirements for DNG. (There is a "Digital Negative (DNG) Specification Patent License", but it does not actually state that there are any patents held on DNG, and the September 2009 statement was made at least 4 years after this license was published).
TIFF/EP began its 5-year revision cycle in 2006. Adobe offered the DNG specification to ISO to be part of ISO's revised TIFF/EP standard. A progress report in October 2008 from ISO about the revision of TIFF/EP stated that the revision "... currently includes two "interoperability-profiles," "IP 1" for processed image data, using ".TIF" extension, and "IP 2" for "raw" image data, ".DNG" extension". It is "IP 2" that is relevant here. A progress report in September 2009 states that "This format will be similar to DNG 1.3, which serves as the starting point for development."
DNG has been exploited by open-source developers. Use by camera makers varies: the largest companies such as Canon, Nikon
, Sony
, and some others, don't use DNG; but smaller companies, and makers of "niche" cameras who might otherwise have difficulty getting support from software companies, frequently use DNG as their native raw image format. (Or in the case of Pentax
, as an optional alternative to their own raw image format). There are of the order of 15 or more such companies, even including a few that specialize in movie cameras.
has to be processed, that is, converted to a photographic rendering of the scene, and then stored in a standard raster graphics
format such as JPEG
. This processing, whether done in-camera or later in a raw file converter, involves a number of operations, typically including:
Note that demosaicing
is only performed for CFA
sensors; it is not required for 3CCD or Foveon X3
sensors.
Cameras and image processing software may also perform additional processing to improve image quality, for example:
When a camera saves a raw file it defers most of this processing; typically the only processing performed is the removal of defective pixels (the DNG specification requires that defective pixels are removed before creating the file). Some camera manufacturers do additional processing before saving raw files; for example, Nikon has been criticized by astrophotographers
for applying noise reduction before saving the raw file.
Some raw formats also allow nonlinear quantization
. This nonlinearity allows the compression of the raw data without visible degradation of the image by removing invisible and irrelevant information from the image. Although noise is discarded this has nothing to do with (visible) noise reduction.
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...
of either a 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 scanner
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
, or motion picture film scanner
Motion picture film scanner
A motion picture film scanner is a device used in digital filmmaking to scan original film for storage as high-resolution digital intermediate files.A film scanner scans original film stock: negative or positive print or reversal/IP...
. Raw files are so named because they are not yet processed and therefore are not ready to be printed
Photographic printing
Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency , or a digital image file projected using an enlarger or digital exposure unit such as a LightJet printer...
or edited with a bitmap graphics editor. Normally, the image is processed by a raw converter in a wide-gamut
Gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
internal colorspace where precise adjustments can be made before conversion to a "positive" file format such as TIFF or JPEG
JPEG
In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
for storage, printing, or further manipulation, which often encodes the image in a device-dependent colorspace. These images are often described as "RAW image files", although there is not actually one single raw file format. In fact there are dozens if not hundreds of such formats in use by different models of digital equipment (like cameras or film scanners).
Raw image files are sometimes called digital negatives, as they fulfill the same role as negatives
Negative (photography)
In photography, a negative may refer to three different things, although they are all related.-A negative:Film for 35 mm cameras comes in long narrow strips of chemical-coated plastic or cellulose acetate. As each image is captured by the camera onto the film strip, the film strip advances so that...
in film photography: that is, the negative is not directly usable as an image, but has all of the information needed to create an image. Likewise, the process of converting a raw image file into a viewable format is sometimes called developing a raw image, by analogy with the film development process used to convert 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...
into viewable prints. The selection of the final choice of image rendering is part of the process of white balancing and color grading
Color grading
Color grading or colour painting, is the process of altering and enhancing the color of a motion picture, video image, or still image either electronically, photo-chemically or digitally. The photo-chemical process is also referred to as color timing and is typically performed at a photographic...
.
Like a photographic negative, a raw digital image may have a wider dynamic range or color gamut
Gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
than the eventual final image format, and it preserves most of the information of the captured image. The purpose of raw image formats is to save, with minimum loss of information, data obtained from the sensor, and the conditions surrounding the capturing of the image (the metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
).
Rationale
Raw image formats are intended to capture as closely as possible (i.e. at the best of the specific sensor's performance) the radiometric characteristics of the scene, that is, physical information about the light intensity and color of the scene.Most raw image file formats store information sensed according to the geometry of the sensor's individual photo-receptive elements (sometimes called pixels) rather than points in the expected final image: sensors with hexagonal element displacement, for example, record information for each of their hexagonally-displaced cells, which a decoding software will eventually transform into the rectangular geometry during "digital developing".
File contents
Raw files contain, by necessity, the information required to produce a viewable image from the camera's sensor data. The structure of raw files, including the ISO standard raw image format ISO 12234-2, TIFF/EPTag Image File Format / Electronic Photography
"Tag Image File Format / Electronic Photography" is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format"...
, often follows a common pattern, that is:
- A short file header which typically contains an indicator of the byte-orderingEndiannessIn computing, the term endian or endianness refers to the ordering of individually addressable sub-components within the representation of a larger data item as stored in external memory . Each sub-component in the representation has a unique degree of significance, like the place value of digits...
of the file, a file identifier and an offset into the main file data - Camera sensor metadataMetadataThe term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
which is required to interpret the sensor image data. This includes the size of the sensor, the attributes of the CFAColor filter arrayIn photography, a color filter array , or color filter mosaic , is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information....
and its color profileICC profileIn color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium... - Image metadataMetadataThe term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
which is required for inclusion in any CMSContent management systemA content management system is a system providing a collection of procedures used to manage work flow in a collaborative environment. These procedures can be manual or computer-based...
environment or databaseDatabaseA database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
. These include the exposure settings, camera/scanner/lens model, date (and, optionally, place) of shoot/scan, authoring information and other. Some raw files contain a standardized metadata section with data in ExifExchangeable image file formatExchangeable image file format is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras , scanners and other systems handling image and sound files recorded by digital cameras...
format. - An image thumbnailThumbnailThumbnails are reduced-size versions of pictures, used to help in recognizing and organizing them, serving the same role for images as a normal text index does for words...
- Optionally a reduced-size image in JPEG format, which can be used for a quick and less computing-intensive preview.
- In the case of motion picture film scans, either the timecode, keycodeKeycodeKeycode may refer to:* scancode, the parcel of data generated when pressing a computer keyboard key ;...
or frame number in the file sequenceFile sequenceIn computing, as well as in non-computing contexts, a file sequence is a well-ordered, collection of files, usually related to each other in some way....
which represents the frame sequence in a scanned reel; this is the most important metadata item, because it allows the file to be ordered in a frame sequenceFile sequenceIn computing, as well as in non-computing contexts, a file sequence is a well-ordered, collection of files, usually related to each other in some way....
(without relying on its filename). - The sensor image data
Many raw file formats (including 3FR (Hasselblad
Hasselblad
Victor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....
), DCR, K25, KDC (Kodak), IIQ (Phase One), CR2 (Canon), ERF (Epson), MEF (Mamiya
Mamiya
is a Japanese company that today manufactures high-end cameras and other related photographic and optical equipment. With headquarters in Tokyo, it has two manufacturing plants and a workforce of over 200 people...
), MOS (Leaf
Leaf Medium Format Photography
Leaf previously a division of Scitex and later Kodak, but now a part of Phase One. Leaf manufactures high end professional digital photography products. In 1991, Leaf introduced the first medium format digital camera back, the Leaf DCB1, nicknamed ‘The Brick’, which had a resolution of 4 million...
), NEF (Nikon), ORF
ORF format
In digital photography, ORF file format is a Raw image format used in Olympus digital cameras. Like all other raw formats, this one contains image information rendered directly by a camera's sensor. ORF files feature so called headers that present image characteristics, such as saturation, color...
(Olympus
Olympus Corporation
is a Japan-based manufacturer of optics and reprography products. Olympus was established on 12 October 1919, initially specializing in microscope and thermometer businesses. Its global headquarters are in Shinjuku, Tokyo, Japan, while its USA operations are based in Center Valley, Pennsylvania,...
), PEF (Pentax
Pentax
Pentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...
), RW2 (Panasonic
Panasonic
Panasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
) and ARW, SRF, SR2 (Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
)) are based on the TIFF file format. These files may deviate from the TIFF standard in a number of ways, including the use of a non-standard file header, the inclusion of additional image tags and the encryption of some of the tagged data.
Panasonic's raw converter corrects geometric distortion and chromatic aberration
Chromatic aberration
In optics, chromatic aberration is a type of distortion in which there is a failure of a lens to focus all colors to the same convergence point. It occurs because lenses have a different refractive index for different wavelengths of light...
on such cameras as the LX3
Lumix
Lumix is Panasonic's brand of digital cameras, ranging from pocket point-and-shoot models to digital SLRs.Compact digital camera DMC-LC5 and DMC-F7 were the first products of the Lumix series released in 2001. They are equipped with Leica lenses....
, with necessary correction information presumably included in the raw.. Phase One (company)'s raw converter Capture One
Capture One
Capture One is professional RAW converter and image editing software developed by Phase One. It is designed for professional photographers who need to process large volumes of high quality images in a fast and efficient workflow...
also offers corrections for geometrical distortion, chromatic aberration
Chromatic aberration
In optics, chromatic aberration is a type of distortion in which there is a failure of a lens to focus all colors to the same convergence point. It occurs because lenses have a different refractive index for different wavelengths of light...
, purple fringing and keystone correction emulating tilt-shift in software, on most raw files from over 100 different cameras . The same holds for Canon's DPP application, at least for all more expensive cameras like all SLRs and the G
DNG
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
, the Adobe digital negative
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
format, is an extension of the TIFF 6.0 format and is compatible with TIFF/EP
Tag Image File Format / Electronic Photography
"Tag Image File Format / Electronic Photography" is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format"...
, and uses various open format
Open format
An open file format is a published specification for storing digital data, usually maintained by a standards organization, which can therefore be used and implemented by anyone. For example, an open format can be implementable by both proprietary and free and open source software, using the typical...
s and/or standards
Open standard
An open standard is a standard that is publicly available and has various rights to use associated with it, and may also have various properties of how it was designed . There is no single definition and interpretations vary with usage....
, including Exif metadata
Exchangeable image file format
Exchangeable image file format is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras , scanners and other systems handling image and sound files recorded by digital cameras...
, XMP metadata
Extensible Metadata Platform
The Adobe Extensible Metadata Platform is a standard, created by Adobe Systems Inc., for processing and storing standardized and proprietary information relating to the contents of a file....
, IPTC metadata
International Press Telecommunications Council
The International Press Telecommunications Council, based in London, United Kingdom, is a consortium of the world's major news agencies and news industry vendors...
, CIE XYZ coordinates
CIE 1931 color space
In the study of color perception, one of the first mathematically defined color spaces is the CIE 1931 XYZ color space, created by the International Commission on Illumination in 1931....
, ICC profile
ICC profile
In color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium...
s, and JPEG
JPEG
In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
.
Sensor image data
In digital photographyDigital photography
Digital photography is a form of photography that uses an array of light sensitive sensors to capture the image focused by the lens, as opposed to an exposure on light sensitive film...
, the raw file plays the role that 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...
plays in film photography
Digital versus film photography
Digital versus film photography has been a topic of debate since the invention of digital cameras towards the end of the 20th Century. Both digital and film photography have advantages and drawbacks...
. Raw files thus contain the full resolution (typically 12- or 14-bit) data as read out from each of the camera's 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...
pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s.
The camera's sensor is almost invariably overlaid with a color filter array
Color filter array
In photography, a color filter array , or color filter mosaic , is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information....
, usually a Bayer filter
Bayer filter
A Bayer filter mosaic is a color filter array for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camcorders, and scanners to create a color image...
, consisting of a mosaic of a 2x2 matrix of red, green, blue and (second) green filters.
One variation on the Bayer filter is the RGBE filter
RGBE filter
In digital photography, the RGBE filter is an alternative color filter array to the Bayer filter . It similarly uses a mosaic of pixel filters, of red, green, blue and "emerald" , and so also requires demosaicing to produce a full-color image...
of the Sony Cyber-shot
Cyber-shot
Cyber-shot is a line of digital cameras made by Sony. The first cyber-shot was made by Sony in 1996. The Cyber-shot range is well known for its proprietary InfoLithium battery pack, the trademark Carl Zeiss lenses, and overall design. Also, all Cyber-shot cameras accept Sony's proprietary Memory...
DSC-F828, which exchanged the green in the RG rows with "emerald"
(a blue-green
Blue-green
Blue-green is a color that is a representation of the color that is between blue and green on a typical traditional old-fashioned RYB color wheel.Blue-green is belongs to the cyan family of colors....
or cyan
Cyan
Cyan from , transliterated: kýanos, meaning "dark blue substance") may be used as the name of any of a number of colors in the blue/green range of the spectrum. In reference to the visible spectrum cyan is used to refer to the color obtained by mixing equal amounts of green and blue light or the...
color). Other sensors, such as the Foveon X3 sensor
Foveon X3 sensor
The Foveon X3 sensor is a CMOSimage sensor for digital cameras, designed by Foveon, Inc. and manufactured by National Semiconductorand Dongbu Electronics....
, capture information directly in RGB form, having three pixel sensors
Active pixel sensor
An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...
in each location, one for each color component; these camera RGB raw data still need to be processed to make an image file, as the RGB values correspond to the responses of the sensors, not to a standard color space like sRGB, though they do not need to be demosaiced
Demosaicing
A demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array...
.
Flatbed
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
and film scanner
Film scanner
A film scanner is a device made for scanning photographic film directly into a computer without the use of any intermediate printmaking. It provides several benefits over using a flatbed scanner to scan in a print of any size: the photographer has direct control over cropping and aspect ratio from...
sensors are typically straight narrow RGB or RGBI (where "I" is intensity) strips that are swept across an image. The HDRi raw data format
HDRi (data format)
The HDRi data format is a 64bit or 32bit data format for saving RAW data of HDR scans including infrared data developed by LaserSoft Imaging.- Data format :- Description :...
is able to store the infrared raw data, which can be used for infrared cleaning
Infrared cleaning
Infrared cleaning is a technique used by some film scanners and flatbed scanners to reduce or remove the effect of dust and scratches upon the finished scan. It works by collecting an additional infrared channel from the scan at the same position and resolution as the three visible colour channels...
, as an additional 16-bit channel. The remainder of the discussion about raw files applies to them as well. (Some scanners do not allow the host system access to the raw data at all, as a speed compromise. The raw data are processed very rapidly inside the scanner to select out the best part of the available dynamic range so only the result is passed to the computer for permanent storage, reducing the amount of data transferred and therefore the bandwidth requirement for any given speed of image throughput.)
To obtain an image from a raw file, this mosaic of data must be converted into standard RGB form. This is often referred to as "raw development".
When converting from the four sensor 2x2 Bayer matrix raw form into single RGB pixels the original 4x12 (or 14) bit data is converted to 4x3x8 bit. The green pair is used to control the overall luminance of the processed output pixel (since the human eye is more sensitive to it - and so green is used as the dominant channel for in-camera black-and-white
Black-and-white
Black-and-white, often abbreviated B/W or B&W, is a term referring to a number of monochrome forms in visual arts.Black-and-white as a description is also something of a misnomer, for in addition to black and white, most of these media included varying shades of gray...
conversions).
If raw format data is available, it can be used in 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...
conversion (instead of the "standard" HDI approach of exposing three separate images, one under exposed, one correct and one over-exposed, and "overlaying" one on top of the other).
Benefits
Nearly all digital cameras can process the image from the sensorCharge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
into a JPEG file using settings for white balance, colour saturation, contrast
Contrast (vision)
Contrast is the difference in visual properties that makes an object distinguishable from other objects and the background. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view...
, and sharpness
Unsharp masking
Unsharp masking is an image manipulation technique, often available in digital image processing software.The "unsharp" of the name derives from the fact that the technique uses a blurred, or "unsharp," positive to create a "mask" of the original image...
that are either selected automatically or entered by the photographer before taking the picture. Cameras that produce raw files save these settings in the file, but defer the processing. This results in an extra step for the photographer, so raw is normally only used when additional computer processing is intended. However, raw has numerous advantages over JPEG such as:
- Higher image quality. Because all the calculations (such as applying gamma correctionGamma correctionGamma correction, gamma nonlinearity, gamma encoding, or often simply gamma, is the name of a nonlinear operation used to code and decode luminance or tristimulus values in video or still image systems...
, demosaicingDemosaicingA demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array...
, white balance, brightnessBrightnessBrightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target...
, contrast, etc...) used to generate pixel values (in RGB format for most images) are performed in one step on the base data, the resultant pixel values will be more accurate and exhibit less posterizationPosterizationPosterization of an image entails conversion of a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another. This was originally done with photographic processes to create posters...
. - Bypassing of undesired steps in the camera's processing, including sharpeningSharpeningSharpening is the process of creating or refining a sharp edge of appropriate shape on a tool or implement designed for cutting. Sharpening is done by grinding away material on the implement with an abrasive substance harder than the material of the implement, followed sometimes by processes to...
and noise reductionNoise reductionNoise reduction is the process of removing noise from a signal.All recording devices, both analogue or digital, have traits which make them susceptible to noise... - JPEG images are typically saved using a lossy compression format (though a lossless JPEG compression is now available). Raw formats are typically either uncompressed or use lossless compression, so the maximum amount of image detail is always kept within the raw file.
- Finer control. Raw conversion software allows users to manipulate more parameters (such as lightness, white balance, hueHueHue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...
, saturation, etc...) and do so with greater variability. For example, the white point can be set to any value, not just discrete preset values like "daylight" or "incandescent". As well, the user can typically see a preview while adjusting these parameters. - Camera raw files have 12 or 14 bits of intensity information, not the gamma-compressedGamma correctionGamma correction, gamma nonlinearity, gamma encoding, or often simply gamma, is the name of a nonlinear operation used to code and decode luminance or tristimulus values in video or still image systems...
8 bits stored in JPEG files (and typically stored in processed TIFF files); since the data is not yet rendered and clipped to a colour space gamutGamutIn color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
, more precision may be available in highlights, shadows, and saturated colours. - The colour space can be set to whatever is desired.
- Different demosaicingDemosaicingA demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array...
algorithms can be used, not just the one coded into the camera. - The contents of raw files include more information, and potentially higher quality, than the converted results, in which the rendering parameters are fixed, the colour gamut is clipped, and there may be quantizationQuantization (image processing)Quantization, involved in image processing, is a lossy compression technique achieved by compressing a range of values to a single quantum value. When the number of discrete symbols in a given stream is reduced, the stream becomes more compressible. For example, reducing the number of colors...
and compressionCompression artifactA compression artifact is a noticeable distortion of media caused by the application of lossy data compression....
artifacts. - Large transformations of the data, such as increasing the exposure of a dramatically under-exposed photo, result in fewer visible artifacts when done from raw data than when done from already rendered image files. Raw data leave more scope for both corrections and artistic manipulations, without resulting in images with visible flaws such as posterizationPosterizationPosterization of an image entails conversion of a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another. This was originally done with photographic processes to create posters...
. - All the changes made on a RAW image file are non-destructive; that is, only the metadata that controls the rendering is changed to make different output versions, leaving the original data unchanged. (This method of editing is not limited to RAW image files. For example, Adobe's Lightroom uses this editing method for all of the file types it can edit, including JPEG and PSD files).
- To some extent, RAW photography eliminates the need to use the HDRI technique, allowing a much better control over the mapping of the scene intensity range into the output tonal range, compared to the process of automatically mapping to JPEGJPEGIn computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
or other 8-bit representation.
Drawbacks
- Camera raw file size are typically 2–6 times larger than JPEG file size. While use of raw formats avoids the compression artifacts inherent in JPEG, fewer images can fit on a given memory cardMemory cardA memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles...
. However, the large sizes and low prices of modern memory cards mitigate this. - Most raw formats use compression or implement light lossless data compressionLossless data compressionLossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...
to reduce the size of the files without affecting image quality. But some others use lossy data compressionLossy data compressionIn information technology, "lossy" compression is a data encoding method that compresses data by discarding some of it. The procedure aims to minimize the amount of data that need to be held, handled, and/or transmitted by a computer...
where quantization and filtering is performed on the image data. Several recent Nikon cameras let photographers choose between no compression, lossless compression or lossy compression for their raw images. - The standard raw image format (ISO 12234-2, TIFF/EPTag Image File Format / Electronic Photography"Tag Image File Format / Electronic Photography" is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format"...
) is not widely accepted. DNGDigital Negative (file format)Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
, the potential candidate for a new standard format, has not been adopted by many major camera companies. (See "Standardization" section). Numerous different raw formats are currently in use and new raw formats keep appearing, while others are abandoned. - Because of the lack of widespread adoption of a standard raw format, more specialized software may be required to open raw files than for standardized formats like JPEG or TIFF. Software developers have to frequently update their products to support the raw formats of the latest cameras but open source implementations like dcrawDcrawdcraw is an open-source computer program which is able to read numerous raw image formats, typically produced by high-end digital cameras. dcraw converts these images into the standard PPM and TIFF image formats...
make it easier. - The time taken in the image workflow is an important factor when choosing between raw and ready-to-use image formats. With modern photo editing software the additional time needed to process raw images has been greatly reduced but it still requires an extra step in workflow.
Software support
Cameras that support raw files typically come with proprietary softwareProprietary software
Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
for conversion of their raw image data into standard RGB images. Other processing and conversion programs
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
and plugins are available from vendors that have either licensed the technology from the camera manufacturer or reverse-engineered
Reverse engineering
Reverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation...
the particular raw format and provided their own processing algorithms.
Adobe Photoshop
Adobe Photoshop
Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated.Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop...
contains extensive support of raw formats since version CS2, as does Adobe Photoshop Lightroom.
Capture One
Capture One
Capture One is professional RAW converter and image editing software developed by Phase One. It is designed for professional photographers who need to process large volumes of high quality images in a fast and efficient workflow...
supports a vast range of raw image files from both DSLRs (Canon, Nikon, Panasonic, Sony etc.) and medium-format cameras (Phase One
Phase One
Phase One is a Danish company specializing in high-end digital photography equipment and software. It manufactures open platform based medium format camera systems and solutions...
, Leaf, Mamiya etc.) .
Paint Shop Pro likewise contains RAW support, although as in the case of most editors updates to the program may be necessary to attain compatibility with newer RAW formats as they are released.
Picasa
Picasa
Picasa is an image organizer and image viewer for organizing and editing digital photos, plus an integrated photo-sharing website, originally created by Idealab in 2002 and owned by Google since 2004. "Picasa" is a blend of the name of Spanish painter Pablo Picasso, the phrase mi casa for "my...
is a free basic editor and organizer that supports most RAW files. IrfanView
IrfanView
IrfanView is a freeware/shareware image viewer for Microsoft Windows that can view, edit, and convert image files and play video/audio files. It is noted for its small size, speed, ease of use, and ability to handle a wide variety of graphic file formats, and has some image creation and painting...
similarly is a freeware/shareware basic editor with support for most RAW files.
Microsoft's Digital Image 2006 recognizes and organizes raw image formats such as .crw, .cr2, and .nef, which are file formats produced by Canon and Nikon, but that product was discontinued in 2007.
Microsoft supplies free software for Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
to integrate viewing and printing into the system's other photo tools; however, this software was last updated in 2005 and does not support many raw files from cameras released subsequently.
The Windows Camera Codec pack allows native viewing of RAW format files from 120 digital SLR cameras from multiple manufacturers in Windows Explorer and Windows Live Photo Gallery, in Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
and Windows 7.
Windows XP and Vista both support the WIC
Windows Imaging Component
The Windows Imaging Component is a Component Object Model based imaging codec framework introduced in Windows Vista and Windows XP Service Pack 3 for working with and processing digital images and image metadata...
codec standard. Products such as Konvertor, Windows Photo Gallery
Windows Photo Gallery
Windows Photo Gallery is a photo management, tagging, and editing tool developed by Microsoft, and is included with all editions of Windows Vista...
, Windows Live Photo Gallery
Windows Live Photo Gallery
Windows Live Photo Gallery is a photo management and photo sharing application released as a part of Microsoft's Windows Live initiative. It is an upgraded version of Windows Photo Gallery, which is a part of Windows Vista....
and FastPictureViewer Professional
Fast Picture Viewer
FastPictureViewer is a commercial 32 and 64-bit image viewer for Windows 7, Vista and XP. Its aim is to facilitate quick review, rating and annotation of large quantities of digital images in the early steps of the digital workflow, with an emphasis on simplicity and speed.As of v1.6, a basic...
can view raw formats for which the necessary WIC
Windows Imaging Component
The Windows Imaging Component is a Component Object Model based imaging codec framework introduced in Windows Vista and Windows XP Service Pack 3 for working with and processing digital images and image metadata...
codecs are installed. Camera manufacturers Canon, Nikon
Nikon
, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
, Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
, Olympus
Olympus Corporation
is a Japan-based manufacturer of optics and reprography products. Olympus was established on 12 October 1919, initially specializing in microscope and thermometer businesses. Its global headquarters are in Shinjuku, Tokyo, Japan, while its USA operations are based in Center Valley, Pennsylvania,...
and Pentax
Pentax
Pentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...
have released WIC codecs, although some manufactures are only providing codec support for the 32-bit versions of Vista. A commercial DNG
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
codec is also available from Ardfry Imaging, while the makers of FastPictureViewer have released a WIC codec pack, adding support for 22 raw formats to Windows in both 32-bit and 64-bit versions, as donationware
Donationware
Donationware is a licensing model that supplies fully operational software to the user and pleads for an optional donation be paid to the programmer or a third-party beneficiary . The amount of the donation may also be stipulated by the author, or it may be left to the discretion of the user,...
.
In 2005, Apple Computer introduced several products which offered raw file support. In January, Apple released iPhoto
IPhoto
iPhoto is a digital photograph manipulation software application developed by Apple Inc. and released with every Macintosh personal computer as part of the iLife suite of digital life management applications...
5, which offered basic support for viewing and editing many raw file formats. In April of that year, Apple introduced a new version of its operating system, Mac OS X v10.4, which added raw support directly to the operating system, as part of the ImageIO framework, which adds raw support automatically to the majority of Mac OS X applications both from Apple (such as Preview, Mac OS X's PDF and image viewing application and Aperture, a photo post-production software package for professionals) as well as all third party applications which make use of the ImageIO frameworks. Semi-regular updates to OS X generally include updated support for new raw file formats introduced in the intervening months by camera makers.
There are many other "raw workflow applications" designed to provide efficient processing and post-processing of raw images, including Helicon Filter
Helicon Filter
Helicon Filter, also referred to as Helicon, Filter, or as HF, is a proprietary commercial and shareware photo editing software program for Microsoft Windows, similar to such programs as Adobe Photoshop and GIMP, developed and published by Helicon Soft Ltd...
, DxO Labs
DxO Labs
DxO Labs is a privately held image processing software company based in Boulogne-Billancourt, France.DxO Optics Pro is a personal computer package which corrects for various optical aberrations, notably image distortion, with corrections tuned to particular lenses and cameras. It also adjusts...
' DxO Optics Pro, Hasselblad
Hasselblad
Victor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....
's Phocus and Bibble Labs' Bibble Pro
Bibble (software)
Bibble is a digital imaging program for multiple platforms by Bibble Labs, designed to assist photographers in post-production work and efficient optimization of images created in the Raw image format.- Bibble 5 :...
. Like Apple Aperture, Adobe Photoshop
Adobe Photoshop
Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated.Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop...
and Lightroom, LaserSoft Imaging's SilverFast
SilverFast
SilverFast is software for scanning and image processing, including photos, documents and slides, developed by LaserSoft Imaging.- History :...
, and PhotoLine, these programs provide sophisticated controls for processing the information stored in the raw file and converting raw files to JPEG or TIFF. Picasa
Picasa
Picasa is an image organizer and image viewer for organizing and editing digital photos, plus an integrated photo-sharing website, originally created by Idealab in 2002 and owned by Google since 2004. "Picasa" is a blend of the name of Spanish painter Pablo Picasso, the phrase mi casa for "my...
, a free image editing and cataloguing program from Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
, can read and display many raw formats, but like iPhoto, Picasa provides only limited tools for processing the data in a raw file.
Light Crafts' LightZone
LightZone
LightZone is a digital photo editor software application from Light Crafts. Its main purpose is to handle the workflow when handling images in various RAW formats. It's comparable to Adobe Systems's Photoshop Lightroom.- History :...
photo editing software provides the ability to edit many raw formats natively. Most tools are raw converters, but LightZone allows a user to edit a raw file as if it were TIFF or JPEG.
Open source software
A portable open sourceOpen source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
program, dcraw
Dcraw
dcraw is an open-source computer program which is able to read numerous raw image formats, typically produced by high-end digital cameras. dcraw converts these images into the standard PPM and TIFF image formats...
, supports most raw formats and can be made to run on operating systems not supported by most commercial software (such as Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
). Libraw is an API library based on dcraw, offering a more convenient interface for reading and converting raw files. HDR PhotoStudio
HDR PhotoStudio
HDR PhotoStudio is an advanced HDR digital imaging software application developed by Unified Color for Microsoft Windows XP/Vista/7 and Apple's Mac OS X...
and AZImage are some of the commercial applications that use Libraw. Jrawio is another API library, written in pure Java code and compliant to the standard Java Image I/O API.
Darktable is an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
RAW workflow tool for Linux and other open unix-like operating systems. Features native 32-bit floating point processing in Lab color space
Lab color space
A Lab color space is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed CIE XYZ color space coordinates....
and plugin architecture.
ExifTool
ExifTool
ExifTool is a free software program for reading, writing, and manipulating image, audio, and video metadata. It is platform independent, available as both a Perl library and command-line application...
supports the reading, writing and editing of metadata in raw image files. ExifTool supports many different types of metadata including Exif, GPS, IPTC
IPTC Information Interchange Model
The Information Interchange Model is a file structure and set of metadata attributes that can be applied to text, images and other media types...
, XMP
Extensible Metadata Platform
The Adobe Extensible Metadata Platform is a standard, created by Adobe Systems Inc., for processing and storing standardized and proprietary information relating to the contents of a file....
, JFIF
JPEG File Interchange Format
The JPEG File Interchange Format is an image file format standard. It is a format for exchanging JPEG encoded files compliant with the JPEG Interchange Format standard. It solves some of JIFs limitations in regard to simple JPEG encoded file interchange...
, GeoTIFF
GeoTIFF
GeoTIFF is a public domain metadata standard which allows georeferencing information to be embedded within a TIFF file. The potential additional information includes map projection, coordinate systems, ellipsoids, datums, and everything else necessary to establish the exact spatial reference for...
, ICC Profile
ICC profile
In color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium...
, Photoshop IRB, FlashPix
FlashPix
FlashPix is a bitmapped computer graphics file format where the image is saved in more than one resolution. Though this makes it larger even than a TIFF file, when a request is sent for the file by a Web browser only the resolution required for the current screen resolution is sent to the browser;...
, AFCP and ID3, as well as the maker notes of many digital cameras.
The latest version of GIMP
GIMP
GIMP is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool and is freely available in versions tailored for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux.In addition to detailed image retouching and...
, a free open source photo editing package, imports many raw formats. Older versions have a plug-in which allows it to read and convert raw files.
ImageMagick
ImageMagick
ImageMagick is an open source software suite for displaying, converting, and editing raster image files. It can read and write over 100 image file formats. ImageMagick is licensed under the Apache 2.0 license.- Features and capabilities:...
, a popular free software suit for image manipulation and conversion, reads many different raw file formats. ImageMagick
ImageMagick
ImageMagick is an open source software suite for displaying, converting, and editing raster image files. It can read and write over 100 image file formats. ImageMagick is licensed under the Apache 2.0 license.- Features and capabilities:...
is available for Linux/Unix, Mac OS, Windows and other platforms.
Photivo is an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
raw processor with a non-destructive 16-bit processing pipeline aimed at flexibility. It runs on Linux, Mac OSX and Windows and integrates tightly with GIMP
GIMP
GIMP is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool and is freely available in versions tailored for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux.In addition to detailed image retouching and...
.
Rawstudio
Rawstudio
Rawstudio is a stand-alone application, using the GTK+ UI toolkit, to read and manipulate images in Raw image formats from digital cameras. It is designed for working rapidly with a large volume of images, unlike similar tools, such as UFRaw, which are designed to work on one image at a...
is another open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
program to read and manipulate images from digital cameras. The main focus is on the streamlined interface to allow for fast review and processing of large image collections.
RawTherapee is an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
raw converter supporting the Linux, Mac OS and Windows operating systems.
UFRaw
UFRaw
UFRaw is an application which can read and manipulate photographs in raw image formats, as created by many digital cameras. UFRaw is available both as a stand-alone utility, as a GIMP and CinePaint plugin, and in F-Spot via the DevelopInUFRaw extension...
is free software based on dcraw. It can be used as a GIMP
GIMP
GIMP is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool and is freely available in versions tailored for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux.In addition to detailed image retouching and...
plugin and is available for most operating systems.
Standardization
Providing a detailed and concise description of the content of raw files is highly problematic. There is no single raw format; formats can be similar or radically different. Different manufacturers use their own proprietary and typically undocumented formats, which are collectively known as raw format. Often they also change the format from one camera model to the next. Several major camera manufacturers, including NikonNikon
, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
, Canon and Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
, encrypt
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
portions of the file in an attempt to prevent third-party tools from accessing them.
This industry-wide situation of inconsistent formatting has concerned many photographers who worry that their valuable raw photos may someday become inaccessible, as computer operating systems and software programs become obsolete and abandoned raw formats are dropped from new software. The availability of high-quality open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
software which decodes raw image formats, particularly dcraw
Dcraw
dcraw is an open-source computer program which is able to read numerous raw image formats, typically produced by high-end digital cameras. dcraw converts these images into the standard PPM and TIFF image formats...
, has helped to alleviate these concerns. An essay by Michael Reichmann and Juergen Specht stated "here are two solutions – the adoption by the camera industry of A: Public documentation of RAW formats; past, present and future, or, more likely B: Adoption of a universal RAW format"; and included in its petition "I am also requesting that your company adopt a universal RAW format. The DNG format has been put forward as such a possible standard, but we are willing to accept any truly open standard as the industry may agree upon". "Planning for [US] Library of Congress Collections" identifies RAW file formats as "less desirable file formats", and identifies DNG
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
as a suggested alternative.
DNG
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
is the only raw image format for which industry-wide buy-in is being sought. It is based upon, and compatible with, the ISO standard raw image format ISO 12234-2, TIFF/EP
Tag Image File Format / Electronic Photography
"Tag Image File Format / Electronic Photography" is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format"...
, and is being used by ISO in their revision of that standard. (See the Standardization section, below.)
The ISO standard raw image format is ISO 12234-2, better known as TIFF/EP
Tag Image File Format / Electronic Photography
"Tag Image File Format / Electronic Photography" is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format"...
. (TIFF/EP also supports "non-raw", or "processed", images). TIFF/EP provided a basis for the raw image formats of a number of cameras. For example, Nikon
Nikon
, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
's NEF raw files are based on TIFF/EP, and include a tag which identifies the version of TIFF/EP they are based on. Adobe's DNG (Digital Negative)
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
raw file format was based on TIFF/EP, and the DNG specification states "DNG ... is compatible with the TIFF-EP standard". Several cameras use DNG as their raw image format, so in that limited sense they use TIFF/EP too.
Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
launched this DNG
Digital Negative (file format)
Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
raw image format in September 2004. By September 2006, several camera manufacturers had started to announce support for DNG in newer camera models, including Leica, Samsung
Samsung
The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...
, Ricoh
Ricoh
or Ricoh, is a Japanese company that was established in 1936 on February 6th, as , a company in the RIKEN zaibatsu. Its headquarters is located in Ricoh Building in Chūō, Tokyo....
, Pentax
Pentax
Pentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...
, Hasselblad
Hasselblad
Victor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....
(native camera support); and, Better Light
Better Light
Better Light, Inc. is a company in San Carlos, California, U.S.A. that manufactures high-end digital scanning backs for view cameras, which are used in many photographic applications including; landscape, commercial advertising, fine art reproduction and architecture.Better Light scan backs...
(export). The Leica Digital-Modul-R (DMR) was first to use DNG as its native format. In September 2009 Adobe stated that there were no known intellectual property encumbrances or license requirements for DNG. (There is a "Digital Negative (DNG) Specification Patent License", but it does not actually state that there are any patents held on DNG, and the September 2009 statement was made at least 4 years after this license was published).
TIFF/EP began its 5-year revision cycle in 2006. Adobe offered the DNG specification to ISO to be part of ISO's revised TIFF/EP standard. A progress report in October 2008 from ISO about the revision of TIFF/EP stated that the revision "... currently includes two "interoperability-profiles," "IP 1" for processed image data, using ".TIF" extension, and "IP 2" for "raw" image data, ".DNG" extension". It is "IP 2" that is relevant here. A progress report in September 2009 states that "This format will be similar to DNG 1.3, which serves as the starting point for development."
DNG has been exploited by open-source developers. Use by camera makers varies: the largest companies such as Canon, Nikon
Nikon
, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
, Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
, and some others, don't use DNG; but smaller companies, and makers of "niche" cameras who might otherwise have difficulty getting support from software companies, frequently use DNG as their native raw image format. (Or in the case of Pentax
Pentax
Pentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...
, as an optional alternative to their own raw image format). There are of the order of 15 or more such companies, even including a few that specialize in movie cameras.
Processing
To be viewed or printed, the output from a camera's image sensorImage 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...
has to be processed, that is, converted to a photographic rendering of the scene, and then stored in a standard raster graphics
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
format such as JPEG
JPEG
In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
. This processing, whether done in-camera or later in a raw file converter, involves a number of operations, typically including:
- decoding – image data of raw files are typically encoded for compression purpose, but also often for obfuscation purpose (e.g. raw files from Canon or Nikon cameras).
- defective pixelDefective pixelDefective pixels are pixels on a liquid crystal display that are not performing as expected. The ISO standard ISO 13406-2 distinguishes between three different types of defective pixels, while hardware companies tend to have further distinguishing types. Similar defects can also occur on CCD or...
removal – replacing data in known bad locations with interpolations from nearby locations - white balancing – accounting for color temperatureColor temperatureColor temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of...
of the light that was used to take the photograph - demosaicingDemosaicingA demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array...
– interpolating the partial raw data received from the color-filteredColor filter arrayIn photography, a color filter array , or color filter mosaic , is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information....
image sensor into a matrix of colored pixels. - noise reductionNoise reductionNoise reduction is the process of removing noise from a signal.All recording devices, both analogue or digital, have traits which make them susceptible to noise...
– trading off detail for smoothness by removing small fluctuations - color translation – converting from the camera native color spaceColor spaceA color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components...
defined by the spectral sensitivitiesSpectral sensitivitySpectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal....
of the image sensor to an output color space (typically sRGB for JPEG) - tone reproduction – the scene luminance captured by the camera sensors and stored in the raw file (with a dynamic rangeDynamic rangeDynamic 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...
of typically 10 or more bits) needs to be rendered for pleasing effect and correct viewing on low-dynamic-range monitors or prints; the tone-reproduction rendering often includes separate tone mappingTone mappingTone mapping is a technique used in image processing and computer graphics to map one set of colors to another in order to approximate the appearance of high dynamic range images in a medium that has a more limited dynamic range...
and gamma compression steps. - compressionImage compressionThe objective of image compression is to reduce irrelevance and redundancy of the image data in order to be able to store or transmit data in an efficient form.- Lossy and lossless compression :...
– for example JPEG compression
Note that demosaicing
Demosaicing
A demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array...
is only performed for CFA
Color filter array
In photography, a color filter array , or color filter mosaic , is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information....
sensors; it is not required for 3CCD or Foveon X3
Foveon X3 sensor
The Foveon X3 sensor is a CMOSimage sensor for digital cameras, designed by Foveon, Inc. and manufactured by National Semiconductorand Dongbu Electronics....
sensors.
Cameras and image processing software may also perform additional processing to improve image quality, for example:
- removal of systematic noise – bias frameBias frameIn digital photography, a bias frame is an image obtained from an opto-electronic image sensor, with no actual exposure time. The image so obtained only contains noise due to the electronics that elaborate the sensor data, and not noise from charge accumulation In digital photography, a bias frame...
subtraction and flat-field correctionFlat-field correctionthumb|210px|The brightness variation due to [[vignetting]], as shown here, can be corrected by selectively brightening the perimeter of the image.Flat-field correction is a technique used to improve quality in digital imaging... - dark frame subtraction
- optical correction – lens distortion correction, vignettingVignettingIn photography and optics, vignetting is a reduction of an image's brightness or saturation at the periphery compared to the image center. The word vignette, from the same root as vine, originally referred to a decorative border in a book. Later, the word came to be used for a photographic...
correction, and color fringingPurple fringingIn photography, and particularly in digital photography, purple fringing is the term for an out-of-focus purple or magenta "ghost" image on a photograph...
correction - contrast enhancementDisplay contrastContrast in visual perception is the difference in appearance of two or more parts of a field seen simultaneously or successively ....
- increasing visual acuityVisual acuityVisual acuity is acuteness or clearness of vision, which is dependent on the sharpness of the retinal focus within the eye and the sensitivity of the interpretative faculty of the brain....
by unsharp maskingUnsharp maskingUnsharp masking is an image manipulation technique, often available in digital image processing software.The "unsharp" of the name derives from the fact that the technique uses a blurred, or "unsharp," positive to create a "mask" of the original image... - dynamic range compressionHigh dynamic range imagingIn 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...
– lighten shadow regions without blowing out highlight regions
When a camera saves a raw file it defers most of this processing; typically the only processing performed is the removal of defective pixels (the DNG specification requires that defective pixels are removed before creating the file). Some camera manufacturers do additional processing before saving raw files; for example, Nikon has been criticized by astrophotographers
Astrophotography
Astrophotography is a specialized type of photography that entails recording images of astronomical objects and large areas of the night sky. The first photographs of an astronomical object were taken in the 1840s, but it was not until the late 19th century that advances in technology allowed for...
for applying noise reduction before saving the raw file.
Some raw formats also allow nonlinear quantization
Quantization (image processing)
Quantization, involved in image processing, is a lossy compression technique achieved by compressing a range of values to a single quantum value. When the number of discrete symbols in a given stream is reduced, the stream becomes more compressible. For example, reducing the number of colors...
. This nonlinearity allows the compression of the raw data without visible degradation of the image by removing invisible and irrelevant information from the image. Although noise is discarded this has nothing to do with (visible) noise reduction.
Annotated list of file extensions
- .3fr (HasselbladHasselbladVictor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....
) - .ari (ARRIFLEXArriflex D-20The Arriflex D-20 is a film-style digital motion picture camera made by Arri first introduced in November 2005. The camera's attributes are its optical viewfinder, modularity, and 35mm-width CMOS sensor. The camera was discontinued in 2008 and the Arriflex D-21 was introduced.- Overview :The D-20...
) - .arw .srf .sr2 (SonySony, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
) - .bay (CasioCasiois a multinational electronic devices manufacturing company founded in 1946, with its headquarters in Shibuya, Tokyo, Japan. Casio is best known for its electronic products, such as calculators, audio equipment, PDAs, cameras, musical instruments, and watches...
) - .crwCamera Image File FormatIn digital photography, the Camera Image File Format file format is a raw image format designed by Canon, and also used as a container format to store metadata in APP0 of JPEG images. Its specification was released on February 12, 1997....
.cr2 (Canon) - .cap .iiq .eip (Phase One)
- .dcs .dcr .drf .k25 .kdc (Kodak)
- .dngDigital Negative (file format)Digital Negative is an open raw image format owned by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products including a free of charge DNG Converter utility...
(AdobeAdobe SystemsAdobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
) - .erf (Epson)
- .fff (Imacon)
- .iiq (Phase One)
- .mef (MamiyaMamiyais a Japanese company that today manufactures high-end cameras and other related photographic and optical equipment. With headquarters in Tokyo, it has two manufacturing plants and a workforce of over 200 people...
) - .mos (LeafLeaf Medium Format PhotographyLeaf previously a division of Scitex and later Kodak, but now a part of Phase One. Leaf manufactures high end professional digital photography products. In 1991, Leaf introduced the first medium format digital camera back, the Leaf DCB1, nicknamed ‘The Brick’, which had a resolution of 4 million...
) - .mrw (MinoltaMinoltaMinolta Co., Ltd. was a Japanese worldwide manufacturer of cameras, camera accessories, photocopiers, fax machines, and laser printers. Minolta was founded in Osaka, Japan, in 1928 as . It is perhaps best known for making the first integrated autofocus 35mm SLR camera system...
) - .nef .nrw (NikonNikon, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
) - .orfORF formatIn digital photography, ORF file format is a Raw image format used in Olympus digital cameras. Like all other raw formats, this one contains image information rendered directly by a camera's sensor. ORF files feature so called headers that present image characteristics, such as saturation, color...
(OlympusOlympus Corporationis a Japan-based manufacturer of optics and reprography products. Olympus was established on 12 October 1919, initially specializing in microscope and thermometer businesses. Its global headquarters are in Shinjuku, Tokyo, Japan, while its USA operations are based in Center Valley, Pennsylvania,...
) - .pef .ptx (PentaxPentaxPentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...
) - .pxn (LogitechLogitechLogitech International S.A. is a global provider of personal peripherals for computers and other digital platforms headquartered in Romanel-sur-Morges, Switzerland. The company develops and markets products like peripheral devices for PCs, including keyboards, mice, microphones, game controllers...
) - .R3D (REDREDCODEREDCODE RAW is a proprietary multimedia audio/video file format owned by Red Digital Cinema Camera Company and featuring lossy compression for video contents and lossless for audio contents...
) - .raf (FujiFujifilmis a multinational photography and imaging company headquartered in Tokyo, Japan.Fujifilm's principal activities are the development, production, sale and servicing of color photographic film, digital cameras, photofinishing equipment, color paper, photofinishing chemicals, medical imaging...
) - .raw .rw2 (PanasonicPanasonicPanasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
) - .raw .rwl .dng (Leica)
- .rwz (RawzorRawzorRawzor is a proprietary lossless image compression software which compresses camera raw images without any loss in image quality or meta-information. It is available for Microsoft Windows and Mac OS X.-Features:* Supports all major raw formats...
) - .srw (SamsungSamsungThe Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...
) - .x3f (SigmaSigma Corporationis a Japanese company founded in 1961, manufacturing cameras, lenses, flashes and other photographic accessories. All Sigma products are produced in the company's own Aizu factory in Bandai, Fukushima, Japan...
)*
External links
- Adobe: Understanding Raw Files"; background on how camera sensors treat raw files
- Open RAW: a working groupWorking groupA working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...
of photographers, software engineers and other people interested in advocating the open documentation of digital camera raw files - Atkins, Bob: "Raw, JPEG, and TIFF"; common file formats compared.
- Coupe, Adam: "The benefits of shooting in RAW"; Article with diagrams explaining the RAW format and its advantages.
- Goldstein, Jim M.: "RAW vs JPEG: Is Shooting RAW Format for Me?"; an editorial.
- Basic Photography lesson in Camera Raw A pros and cons approach to the discussion of shooting in Camera Raw
- Clevy, Laurent: "Inside the Canon RAW format v2: understanding the .CR2 file format"
- Foi, Alessandro: "Signal-dependent noise modeling, estimation, and removal for digital imaging sensors"; with Matlab software and raw-data samples of Canon, Nikon, Fujifilm cameras.