Exchangeable image file format
Encyclopedia
Exchangeable image file format (Exif) is a standard that specifies the formats
for image
s, sound
, and ancillary tags used by digital camera
s (including smartphone
s), scanners
and other systems handling image and sound files recorded by digital cameras. The specification uses the following existing file formats with the addition of specific metadata tags: JPEG
DCT for compressed image files, TIFF
Rev. 6.0 (RGB or YCbCr) for uncompressed image files, and RIFF WAV
for audio files (Linear PCM
or ITU-T G.711
μ-Law PCM for uncompressed audio data, and IMA
-ADPCM for compressed audio data). It is not supported in JPEG 2000
, PNG, or GIF
.
This standard consists of the Exif image file specification and the Exif audio file specification.
(JEIDA). Version 2.1 of the specification is dated June 12, 1998, and the latest, version 2.3 dated April 2010, was jointly formulated by JEITA
and CIPA
. Though the specification is not currently maintained by any industry or standards
organization, almost all camera manufacturers make use of it.
The metadata tags defined in the Exif standard cover a broad spectrum:
, Exif, TIFF/EP
, and DCF
standards. For descriptive metadata, there is an overlap between Exif and IPTC Information Interchange Model
info, which also can be embedded in a JPEG file.
When Exif is employed for JPEG
files, the Exif data are stored in one of JPEG's defined utility Application Segments, the APP1 (segment marker 0xFFE1), which in effect holds an entire TIFF file within. When Exif is employed in TIFF files (also when used as "an embedded TIFF file" mentioned earlier), the TIFF Private Tag 0x8769 defines a sub-Image File Directory (IFD) that holds the Exif specified TIFF Tags. In addition, Exif also defines a Global Positioning System
sub-IFD using the TIFF Private Tag 0x8825, holding location information, and an "Interoperability IFD" specified within the Exif sub-IFD, using the Exif tag 0xA005.
Formats specified in Exif standard are defined as folder structures that are based on Exif-JPEG and recording formats for memory. When these formats are used as Exif/DCF files together with the DCF specification (for better interoperability among devices of different types), their scope shall cover devices, recording media, and application software that handle them.
. Recorded GPS data can also be added to any digital photograph on a computer, either by correlating the time stamps of the photographs with a GPS record
from a hand-held GPS receiver or manually using a map or mapping software. The process of adding geographic information to a photograph is known as geocoding
. Photo sharing communities like Panoramio
, locr or Flickr
equally allow their users to upload geocoded pictures or to add geolocation information online.
Most of Nokia
's Nseries mobile phones (such as the N95
) are equipped with a GPS receiver, and using Location Tagger, a piece of software from Nokia Beta Labs
. All captured images are tagged with corresponding GPS coordinates when a GPS signal is available. The second generation of iPhone
(known as the iPhone 3G) by Apple Inc. is also equipped with a GPS receiver, and uses the receiver to geotag photographs taken with the device. Subsequent generations (the iPhone 3GS, 4 & 4S) also support this feature. The first generation iPhone is not equipped with GPS, and uses a service provided by Skyhook
to triangulate and approximate the location at which the picture was taken using nearby cellular phone towers and WiFi
hot-spot signal strength data. The Skyhook service provides approximate GPS location information which is then added to the Exif data associated with the picture. Also mobile phones with the Android operating system as well as BlackBerry
smartphones with a camera and builtin GPS or Bluetooth GPS addons can geotag images with the included camera application.
recognize and preserve Exif data when writing to a modified image, this is not the case for most older programs. Many image gallery programs also recognise Exif data and optionally display it alongside the images.
Software libraries, such as libexif for C and Exiv2 for C++, Metadata Extractor for Java, or Image::ExifTool
for Perl, parse Exif data from files and read/write Exif tag values.
and XMP
metadata in images.
Extensible Metadata Platform
(XMP) was created by Adobe Systems
to be a better metadata format for photography and image processing. However, it is generally unsupported in cameras.
In Windows Mobile (Pocket PC), freeware XnView Pocket can display the Exif data.
On Mac OS X
10.4 and above, this information may be viewed in the Finder by doing Get Info on a file and expanding the More Info section.
On Unix
systems using the GNOME
desktop environment
, a subset of Exif data can be seen by right clicking the file in the Nautilus file manager and selecting properties. In KDE
, it can be seen by right clicking in the Dolphin
file manager, selecting "Properties" and then "Information". It is also possible to view and edit Exif data in digiKam
photo management program. Most Unix image viewers give the full set of Exif data.
There are many software tools available which allow both viewing and editing of Exif data. The Opanda IExif Viewer is a free stand-alone application for viewing Exif data and also a plug-in for Internet Explorer
and Firefox on Windows platforms. EXIFeditor is another free application that allows editing of EXIF information. It allows examination of detailed Exif data online by right clicking on an image. FxIF and Exif Viewer are multi-platform extensions for Firefox that display Exif data in the image properties dialog. This feature is native in the web browser Opera
, under image properties.
Retrieval of detailed Exif data not usually displayed by other programs can be accomplished using ExifTool
which runs in Perl
, and is available for all platforms.
For AmigaOS/MorphOS, SView5 as well as .NET covers a lot of the previously mentioned functionality.
To deal with the privacy problems that Exif may pose to those who share their photographs with others, specialized metadata removal tool
s which can remove Exif exist.
The following table shows Exif data for a photo made with a typical digital camera. Notice that authorship and copyright information is generally not provided in the camera's output, so it must be filled in during later stages of processing.
images using a structure similar to that of a FlashPix
file. These FlashPix extensions allow meta information to be preserved when converting between FPXR JPEG images and FlashPix images. FPXR information may be found in images from some models of digital cameras by Kodak and Hewlett-Packard
. Below is an example of the FPXR information found in a JPEG image from a Kodak EasyShare V570
digital camera:
audio files, and defines a number of tags for storing meta information such as artist, copyright, creation date, and more in these files. The following table gives an example of Exif information found in a WAV file written by the Pentax Optio WP digital camera:
File format
A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...
for image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
s, sound
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
, and ancillary tags used by digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s (including smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...
s), scanners
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 other systems handling image and sound files recorded by digital cameras. The specification uses the following existing file formats with the addition of specific metadata tags: 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....
DCT for compressed image files, TIFF
Tagged Image File Format
TIFF is a file format for storing images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems...
Rev. 6.0 (RGB or YCbCr) for uncompressed image files, and RIFF WAV
WAV
Waveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...
for audio files (Linear PCM
Pulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
or ITU-T G.711
G.711
G.711 is an ITU-T standard for audio companding. It is primarily used in telephony. The standard was released for usage in 1972. Its formal name is Pulse code modulation of voice frequencies. It is required standard in many technologies, for example in H.320 and H.323 specifications. It can also...
μ-Law PCM for uncompressed audio data, and IMA
Interactive Multimedia Association
The Interactive Multimedia Association was an industry association which developed a set of audio algorithms. The most important is the ADPCM algorithm which is in use by Apple and Microsoft....
-ADPCM for compressed audio data). It is not supported in JPEG 2000
JPEG 2000
JPEG 2000 is an image compression standard and coding system. It was created by the Joint Photographic Experts Group committee in 2000 with the intention of superseding their original discrete cosine transform-based JPEG standard with a newly designed, wavelet-based method...
, PNG, or GIF
GIF
The Graphics Interchange Format is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability....
.
This standard consists of the Exif image file specification and the Exif audio file specification.
Background
Exif was created by the Japan Electronic Industries Development AssociationJapan Electronic Industries Development Association
The was an industry research, development, and standards body for electronics in Japan. It was merged with EIAJ to form JEITA on November 1, 2000.JEIDA was similar to SEMTEC of the USA, ECMA of Europe....
(JEIDA). Version 2.1 of the specification is dated June 12, 1998, and the latest, version 2.3 dated April 2010, was jointly formulated by JEITA
Japan Electronics and Information Technology Industries Association
The is a Japanese trade organization for the electronics and IT industries. It was formed in 2000 from two earlier organizations, the Electronic Industries Association of Japan and the Japan Electronic Industries Development Association.-See also:...
and CIPA
Camera & Imaging Products Association
, is a Japan-based organization set up in July 2002 to deal with technologies related to photography. Its members are engaged with the production of film-based and digital cameras, and other related equipment....
. Though the specification is not currently maintained by any industry or standards
Standardization
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....
organization, almost all camera manufacturers make use of it.
The metadata tags defined in the Exif standard cover a broad spectrum:
- Date and time information. Digital cameras will record the current date and time and save this in the metadata.
- Camera settings. This includes static information such as the camera model and make, and information that varies with each image such as orientation (rotation), apertureApertureIn optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...
, shutter speedShutter speedIn photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....
, focal lengthFocal lengthThe focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus...
, metering modeMetering modeIn photography, the metering mode refers to the way in which a camera determines the exposure.- Examples of metering modes :Cameras generally allow the user to select between spot, center-weighted average, or multi-zone metering modes....
, and ISO speed information. - A 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...
for previewing the picture on the camera's LCD screen, in file managers, or in photo manipulation software. - Descriptions
- Copyright information.
Technical
The Exif tag structure is borrowed from TIFF files. On several image specific properties, there is a large overlap between the tags defined in the TIFFTagged Image File Format
TIFF is a file format for storing images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems...
, Exif, 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 DCF
Design rule for Camera File system
Design rule for Camera File system is a JEITA specification which defines a file system for digital cameras, including the directory structure, file naming method, character set, file format, and metadata format. It is currently the de facto industry standard for digital still cameras...
standards. For descriptive metadata, there is an overlap between Exif and IPTC Information Interchange Model
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...
info, which also can be embedded in a JPEG file.
When Exif is employed for 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....
files, the Exif data are stored in one of JPEG's defined utility Application Segments, the APP1 (segment marker 0xFFE1), which in effect holds an entire TIFF file within. When Exif is employed in TIFF files (also when used as "an embedded TIFF file" mentioned earlier), the TIFF Private Tag 0x8769 defines a sub-Image File Directory (IFD) that holds the Exif specified TIFF Tags. In addition, Exif also defines a Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
sub-IFD using the TIFF Private Tag 0x8825, holding location information, and an "Interoperability IFD" specified within the Exif sub-IFD, using the Exif tag 0xA005.
Formats specified in Exif standard are defined as folder structures that are based on Exif-JPEG and recording formats for memory. When these formats are used as Exif/DCF files together with the DCF specification (for better interoperability among devices of different types), their scope shall cover devices, recording media, and application software that handle them.
Geolocation
The Exif format has standard tags for location information. Currently, a few cameras and a growing number of mobile phones have a built-in GPS receiver that stores the location information in the Exif header when the picture is taken. Some other cameras have a separate GPS receiver that fits into the flash connector or hot shoeHot shoe
A hot shoe is a mounting point on the top of a camera to attach a flash unit.- Design :The hot shoe is shaped somewhat like an inverted, squared-off "U" of metal. The matching adapter on the bottom of the flash unit slides in from the back of the camera and is sometimes secured by a clamping screw...
. Recorded GPS data can also be added to any digital photograph on a computer, either by correlating the time stamps of the photographs with a GPS record
GPS tracking
A GPS tracking unit is a device that uses the Global Positioning System to determine the precise location of a vehicle, person, or other asset to which it is attached and to record the position of the asset at regular intervals...
from a hand-held GPS receiver or manually using a map or mapping software. The process of adding geographic information to a photograph is known as geocoding
Geocoded photo
A geotagged photograph is a photograph which is associated with a geographical location by geotagging. Usually this is done by assigning at least a latitude and longitude to the image, and optionally altitude, compass bearing and other fields may also be included.In theory, every part of a picture...
. Photo sharing communities like Panoramio
Panoramio
Panoramio is a geolocation-oriented photo sharing website. Accepted photos uploaded to the site can be accessed as a layer in Google Earth and Google Maps, with new photos being added at the end of every month. The site's goal is to allow Google Earth users to learn more about a given area by...
, locr or Flickr
Flickr
Flickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
equally allow their users to upload geocoded pictures or to add geolocation information online.
Most of Nokia
Nokia
Nokia Corporation is a Finnish multinational communications corporation that is headquartered in Keilaniemi, Espoo, a city neighbouring Finland's capital Helsinki...
's Nseries mobile phones (such as the N95
Nokia N95
The Nokia N95 is a smartphone produced by Nokia as part of their Nseries line of portable devices. It was released in 2007. The N95 runs Symbian OS v9.2, with a S60 3rd Edition user interface. The phone has a two-way sliding mechanism, which can be used to access either media playback buttons or...
) are equipped with a GPS receiver, and using Location Tagger, a piece of software from Nokia Beta Labs
Nokia Beta Labs
Nokia Beta Labs is a website through which Nokia makes its beta applications available for public download.-Overview:The applications provided by Beta Labs are still in development, but are considered "mature" enough to be released in order to be tested by users worldwide. Anyone can submit...
. All captured images are tagged with corresponding GPS coordinates when a GPS signal is available. The second generation of iPhone
IPhone
The iPhone is a line of Internet and multimedia-enabled smartphones marketed by Apple Inc. The first iPhone was unveiled by Steve Jobs, then CEO of Apple, on January 9, 2007, and released on June 29, 2007...
(known as the iPhone 3G) by Apple Inc. is also equipped with a GPS receiver, and uses the receiver to geotag photographs taken with the device. Subsequent generations (the iPhone 3GS, 4 & 4S) also support this feature. The first generation iPhone is not equipped with GPS, and uses a service provided by Skyhook
Skyhook Wireless
Skyhook Wireless is a Boston-based company that developed a technology for determining geographical location using Wi-Fi as the underlying reference system. Using the MAC addresses of nearby wireless access points and proprietary algorithms, Skyhook's Wi-Fi Positioning System WPS can determine...
to triangulate and approximate the location at which the picture was taken using nearby cellular phone towers and WiFi
WIFI
WIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
hot-spot signal strength data. The Skyhook service provides approximate GPS location information which is then added to the Exif data associated with the picture. Also mobile phones with the Android operating system as well as BlackBerry
BlackBerry
BlackBerry is a line of mobile email and smartphone devices developed and designed by Canadian company Research In Motion since 1999.BlackBerry devices are smartphones, designed to function as personal digital assistants, portable media players, internet browsers, gaming devices, and much more...
smartphones with a camera and builtin GPS or Bluetooth GPS addons can geotag images with the included camera application.
Program support
Exif data are embedded within the image file itself. While many recent image manipulation programsGraphics software
In computer graphics, graphics software or image editing software is a program or collection of programs that enable a person to manipulate visual images on a computer....
recognize and preserve Exif data when writing to a modified image, this is not the case for most older programs. Many image gallery programs also recognise Exif data and optionally display it alongside the images.
Software libraries, such as libexif for C and Exiv2 for C++, Metadata Extractor for Java, or Image::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...
for Perl, parse Exif data from files and read/write Exif tag values.
Problems
Apart from not being a maintained standard, the Exif format has a number of drawbacks, mostly relating to its use of legacy file structures.- The derivation of Exif from the TIFFTagged Image File FormatTIFF is a file format for storing images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems...
file structure using offset pointers in the files means that data can be spread anywhere within a file, which means that software is likely to corrupt any pointers or corresponding data that it doesn't decode/encode. For this reason most image editors damage or remove the Exif metadata to some extent upon saving.
- The standard defines a MakerNote tag, which allows camera manufacturers to place any custom format metadata in the file. This is used increasingly by camera manufacturers to store myriad camera settings not listed in the Exif standard, such as shooting modes, post-processing settings, serial number, focusing modes, etc. As this tag format is proprietary and manufacturer-specific, it can be prohibitively difficult to retrieve this information from an image (or properly preserve it when rewriting an image). Some manufacturers encrypt portions of the information; for example, Nikon encrypts the detailed lens data in their newer MakerNote data versions.
- The standard only allows TIFFTagged Image File FormatTIFF is a file format for storing images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems...
or 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....
files — there is no provision for a "raw" file type which would be a direct data dump from the sensor device. This has caused camera manufacturers to invent many proprietary, incompatible "raw" file formats. To solve this problem, Adobe developed the 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...
format (a TIFF-based raw file format), in hopes that manufacturers would standardize on a single, raw file format.
- The Exif standard specifically states that color depth is always 24 bits. However, many modern cameras, such as the Nikon D70Nikon D70The Nikon D70 is a digital single-lens reflex camera, introduced at the 2004 PMA Annual Convention and Trade Show, as Nikon's first affordable consumer-level digital SLR, and a competitor to the Canon EOS 300D. It was often sold in a "kit-package" with the Nikon 18-70mm AF-S lens...
which captures 36 bits of color per pixel, can capture significantly more. Since Exif/DCF files cannot represent this color depth, many manufacturers have developed proprietary, non-compatible Raw image formatRAW image formatA 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...
s.
- Some digital cameras can also capture video. The Exif standard has no provision for video files.
- Exif is very often used in images created by scanners, but the standard makes no provisions for any scanner-specific information.
- Photo manipulation software sometimes fails to update the embedded thumbnail after an editing operation, possibly causing the user to inadvertently publish compromising information.
- Exif metadata are restricted in size to 64 kB in 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....
images because according to the specification this information must be contained within a single 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....
APP1 segment. Although the FlashPix extensions allow information to span multiple 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....
APP2 segments, these extensions are not commonly used. This has prompted some camera manufacturers to develop non-standard techniques for storing the large preview images used by some digital cameras for LCDLiquid crystal displayA liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
review. These non-standard extensions are commonly lost if a user re-saves the image using image editor software, possibly rendering the image incompatible with the original camera that created it.
- There is no way to record time-zone information along with the time, thus rendering the stored time ambiguous.
- There is no field to record readouts of a camera's accelerometers or inertial navigation systemInertial navigation systemAn inertial navigation system is a navigation aid that uses a computer, motion sensors and rotation sensors to continuously calculate via dead reckoning the position, orientation, and velocity of a moving object without the need for external references...
. Such data could help to establish the relationship between the image sensor’s XYZ coordinate system and the gravity vector (i.e., which way is down in this image). It could also establish relative camera positions or orientations in a sequence of photos.
- Since the Exif tag contains information about the photo, it can pose a privacy issue. For example, a photo taken with a GPS-enabled camera can reveal the exact location it was taken, which is undesirable in some situations. By removing the Exif tag with software such as ExifToolExifToolExifTool 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...
before publishing, the photographer can avoid possible problems.
Related standards
Metadata Working Group was formed by a consortium of companies in 2006 (according to their web page) or 2007 (as stated in their own press release). It released its first document on 24 September 2008, giving recommendations concerning the use of Exif, IPTCIPTC 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...
and 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....
metadata in images.
Extensible Metadata Platform
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....
(XMP) was created by Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
to be a better metadata format for photography and image processing. However, it is generally unsupported in cameras.
Viewing and editing Exif data
In the original release of Windows XP, a subset of the Exif information may be viewed by right clicking on an image file and clicking properties; from the properties dialog click the Summary tab and then the Advanced button. However, this can damage certain Exif headers if changes are applied. As of the release of Service Pack 3, Windows XP still shows evidence of corrupting Exif tags when modifying JPG file properties via the file properties window.In Windows Mobile (Pocket PC), freeware XnView Pocket can display the Exif data.
On Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
10.4 and above, this information may be viewed in the Finder by doing Get Info on a file and expanding the More Info section.
On 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...
systems using the GNOME
GNOME
GNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
desktop environment
Desktop environment
In graphical computing, a desktop environment commonly refers to a style of graphical user interface derived from the desktop metaphor that is seen on most modern personal computers. These GUIs help the user in easily accessing, configuring, and modifying many important and frequently accessed...
, a subset of Exif data can be seen by right clicking the file in the Nautilus file manager and selecting properties. In KDE
KDE
KDE is an international free software community producing an integrated set of cross-platform applications designed to run on Linux, FreeBSD, Microsoft Windows, Solaris and Mac OS X systems...
, it can be seen by right clicking in the Dolphin
Dolphin (software)
Dolphin is a free and open source software file manager for and part of the KDE Software Compilation. It is the default file manager in the current version, KDE Software Compilation 4, and can be optionally installed on K Desktop Environment 3...
file manager, selecting "Properties" and then "Information". It is also possible to view and edit Exif data in digiKam
DigiKam
digiKam is an image organizer and editor using KDE Platform. It runs on most known desktop environments and window managers if the required libraries are installed. It supports all major image file formats, and can organize collections of photographs in directory-based albums, or dynamic albums by...
photo management program. Most Unix image viewers give the full set of Exif data.
There are many software tools available which allow both viewing and editing of Exif data. The Opanda IExif Viewer is a free stand-alone application for viewing Exif data and also a plug-in for Internet Explorer
Internet Explorer
Windows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
and Firefox on Windows platforms. EXIFeditor is another free application that allows editing of EXIF information. It allows examination of detailed Exif data online by right clicking on an image. FxIF and Exif Viewer are multi-platform extensions for Firefox that display Exif data in the image properties dialog. This feature is native in the web browser Opera
Opera (web browser)
Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
, under image properties.
Retrieval of detailed Exif data not usually displayed by other programs can be accomplished using 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...
which runs in Perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...
, and is available for all platforms.
For AmigaOS/MorphOS, SView5 as well as .NET covers a lot of the previously mentioned functionality.
To deal with the privacy problems that Exif may pose to those who share their photographs with others, specialized metadata removal tool
Metadata removal tool
Metadata removal tool or Metadata scrubber is a type of privacy software built to protect the privacy of its users by removing potentially privacy-compromising metadata from files before they are shared with others Metadata removal tool or Metadata scrubber is a type of privacy software built to...
s which can remove Exif exist.
Example
| Tag | Value |
|---|---|
| Manufacturer | CASIO |
| Model | QV-4000 |
| Orientation (rotation) | top - left [8 possible values] |
| Software | Ver1.01 |
| Date and Time | 2003:08:11 16:45:32 |
| YCbCr Positioning | centered |
| Compression | JPEG compression |
| x-Resolution | 72.00 |
| y-Resolution | 72.00 |
| Resolution Unit | Inch |
| Exposure Time | 1/659 sec. |
| FNumber | f/4.0 |
| ExposureProgram | Normal program |
| Exif Version | Exif Version 2.1 |
| Date and Time (original) | 2003:08:11 16:45:32 |
| Date and Time (digitized) | 2003:08:11 16:45:32 |
| ComponentsConfiguration | Y Cb Cr - |
| Compressed Bits per Pixel | 4.01 |
| Exposure Bias | 0.0 |
| MaxApertureValue | 2.00 |
| Metering Mode | Pattern |
| Flash | Flash did not fire. |
| Focal Length | 20.1 mm |
| MakerNote | 432 bytes unknown data |
| FlashPixVersion | 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;... Version 1.0 |
| Color Space | sRGB |
| PixelXDimension | 2240 |
| PixelYDimension | 1680 |
| File Source | DSC |
| InteroperabilityIndex | R98 |
| InteroperabilityVersion | (null) |
FlashPix extensions
The Exif specification also includes a description of FPXR (FlashPix-Ready) information which may be stored in APP2 of JPEGJPEG
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....
images using a structure similar to that of a 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;...
file. These FlashPix extensions allow meta information to be preserved when converting between FPXR JPEG images and FlashPix images. FPXR information may be found in images from some models of digital cameras by Kodak and Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
. Below is an example of the FPXR information found in a JPEG image from a Kodak EasyShare V570
Kodak EasyShare V570
The Kodak EasyShare V570 is a high-end digital camera manufactured by Eastman Kodak. Announced on January 2, 2006, it is an upper model in the range, which was advertised as $400 in The United States in January 2006...
digital camera:
| Tag | Value |
|---|---|
| Code Page | 1200 |
| Used Extension Numbers | 1 |
| Extension Name | Screen nail |
| Extension Class ID | 10000230-6FC0-11D0-BD01-00609719A180 |
| Extension Persistence | Invalidated By Modification |
| Extension Create Date | 2003:03:29 17:47:50 |
| Extension Modify Date | 2003:03:29 17:47:50 |
| Creating Application | Picoss |
| Extension Description | Presized image for LCD display |
| Storage-Stream Pathname | /.Screen Nail_bd0100609719a180 |
| Screen Nail | (124498 bytes of data containing 640x480 JPEG preview image) |
Exif audio files
The Exif specification describes the RIFF file format used for WAVWAV
Waveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...
audio files, and defines a number of tags for storing meta information such as artist, copyright, creation date, and more in these files. The following table gives an example of Exif information found in a WAV file written by the Pentax Optio WP digital camera:
| Tag | Value |
|---|---|
| Encoding | Microsoft PCM |
| Num Channels | 1 |
| Sample Rate | 7872 |
| Avg Bytes Per Sec | 7872 |
| Bits Per Sample | 8 |
| Date Created | 2005:08:08 |
| Exif Version | 0220 |
| Related Image File | IMGP1149.JPG |
| Time Created | 16:23:35 |
| Make | PENTAX Corporation |
| Model | PENTAX Optio WP |
| MakerNote | (2064 bytes of data) |
MakerNote data
The 'MakerNote' tag contains image information normally in a proprietary binary format. Some of these manufacturer-specific formats have been decoded:- OZHiker: Agfa, Canon, Casio, Epson, Fujifilm, Konica/Minolta, Kyocera/Contax, Nikon, Olympus, Panasonic, Pentax/Asahi, Ricoh, Sony
- Kamisaka: Canon, Casio, FujiFilm, ISL, KDDI, Konica/Minolta, Mamiya, Nikon, Panasonic, Pentax, Ricoh, Sigma, Sony, WWL
- X3F Info: Sigma/Foveon
- ExifToolExifToolExifTool 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...
: Canon, Casio, FujiFilm, GE, HP, JVC/Victor, Kodak, Leaf, Minolta/Konica-Minolta, Nikon, Olympus/Epson, Panasonic/Leica, Pentax/Asahi, Reconyx, Ricoh, Samsung, Sanyo, Sigma/Foveon, Sony - Olypedia: Olympus
See also
- Comparison of image viewersComparison of image viewersThis article presents a comparison of image viewers and image organizers which can be used for image viewing.-General information:Note 1: Adobe Bridge comes included in the price with the Adobe Creative Suite CS2, Adobe Production Studio and Photoshop Elements 4 for Mac OS X...
(Exif view/edit functions) - Design rule for Camera File systemDesign rule for Camera File systemDesign rule for Camera File system is a JEITA specification which defines a file system for digital cameras, including the directory structure, file naming method, character set, file format, and metadata format. It is currently the de facto industry standard for digital still cameras...
(DCF) - Digital photographyDigital photographyDigital 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...
- eXtensible Metadata PlatformExtensible Metadata PlatformThe 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....
(XMP) - Geocoded photoGeocoded photoA geotagged photograph is a photograph which is associated with a geographical location by geotagging. Usually this is done by assigning at least a latitude and longitude to the image, and optionally altitude, compass bearing and other fields may also be included.In theory, every part of a picture...
- Image file formatsImage file formatsImage file formats are standardized means of organizing and storing digital images. Image files are composed of either pixels, vector data, or a combination of the two. Whatever the format, the files are rasterized to pixels when displayed on most graphic displays...
- IPTC Information Interchange ModelIPTC Information Interchange ModelThe Information Interchange Model is a file structure and set of metadata attributes that can be applied to text, images and other media types...
- Metadata Working GroupMetadata Working GroupMetadata Working Group was formed in 2006 by Adobe Systems, Apple, Canon, Microsoft and Nokia. Sony joined later in 2008.The focus of the group is to advance the interoperability of metadata stored in digital media. Its first specification, , defined the interoperability among Exif, IIM , and XMP...
- Tag Image File Format / Electronic PhotographyTag 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)
External links
- Exif standard version 2.3
- Exif standard version 2.21
- Exif 2.2 Specification as PDF file or as HTML
- Exif in the TIFF Tags Directory
- Metadata working group