Exchangeable Image File Format

The Exchangeable Image File Format ( official abbreviation is Exif, not EXIF ) is a standard format of the Japan Electronic and Information Technology Industries Association ( JEITA ) for the storage of metadata in digital images. The latest version of the standard ( 2.3, April 2010, last revision in May 2013 ) was developed by a collaboration between the JEITA with the Japanese organization also CIPA ( successor organization to the JCIA - Japan Camera Industry Association ) formulated.

• 6.1 Software and Tools

Applications

Exif data is written directly to the file of images of the JFIF (JPEG) or TIFF - the so-called header ( area at the beginning of the image file, even before the actual image information ). Meanwhile sets as good as any digital camera these additional information about the recording in the picture, the camera application on most handsets create images with Exif data.

Many image editing programs and other software can output this data. In addition, can be used for audio files exif data.

Exif entries

Almost all modern digital cameras dominate the Exif standard and save with every shot numerous recording parameters, such as:

• Date and Time
• Orientation ( rotate the image by 90, 180 or 270 ° )
• Focal length
• Exposure time
• Aperture setting
• Exposure Program
• ISO ( " sensitivity to light" )
• GPS coordinates (see photo localization Geo - Imaging)
• Preview image ( " thumbnail " )

Other useful information can be added later in the form of so-called IPTC (International Press Telecommunications Council ). The IPTC standard is next Exif another standard, which comes mainly in photojournalism used. Examples of typical IPTC fields are:

• Comment ( eg in the form of a picture description)
• Artist Name
• Notes on copyright file

Examples of Exif tags

There are various information in the EXIF ​​data, they are in the form of " tags" ( engl. "tag" = symbol, marker ) were deposited. The tags are composed of a pair of (a) a name in accordance with Exif standard, and ( b ) a value, numeric or alphanumeric. The national language representations of the names and the formatting of the ( numerical ) values ​​is achieved by displaying programs. The tags are standardized and provide information about the camera settings under which the picture was taken, such as the following:

In addition to the standard fields, manufacturers can still insert specific " Maker Notes", the vendor-defined, contains proprietary information that is either not defined by the Exif standard, or the contents of which are not disclosed for other reasons. Examples:

• Focus Mode
• AF Point
• Focus Distance

Example of EXIF data from a Sony Alpha 380

The data of the lens can be used by Panorama programs to correct certain aberrations before assembling. This camera and the associated software uses the data also to the peripheral light correction to eliminate slight vignetting by brightening.

Possible Problems

By adding metadata (date, time, location, preview ) to the original (possibly unintentionally) published details that were not meant for the target group. So get with the help of a suitable program remove all unwanted Exif data before sharing photos by e -mail or other media or release on a website. For example, the whereabouts of the fugitive John McAfee by the reckless publication was of known during an interview with a shot by the journalists photo with GPS coordinates.

When editing photos with common image editing programs some exif data can be changed so that they are no longer displayed with common image viewers. Nikon reports to (reproduced here in abbreviated form ) on a support page the following:

Versions

• JEITA Exif Version 2.1 from 1 June 1998
• JEITA Exif Version 2.2 (project name "Exif Print") dated 20 February 2002 ( published between February and April 2002)
• JEITA Exif version 2.21 ( released in September 2003, immediately after DCF 2.0 ) ( with Adobe RGB support) of 11 July 2003
• JEITA Exif version 2.3 of 26 April 2010, last revision in May 2013