Standards: Exif

Digital cameras embed technical metadata, called Exif data, into image files (primarily JPEG and TIFF formats) they create.

Exif’s primary feature is its ability to record camera information in an image file at the point of capture. Some common data fields include the camera make and model, its serial number, the date and time of image capture, the shutter speed, the aperture, the lens used and the ISO speed setting. Exif metadata often includes other technical details, such as white balance and distance to the subject.

Exif metadata can also include thumbnails along with technical and primary image data in a single image file.

The Exif standard was established in 1985 by the JCIA (Japan Camera Industry Association), the predecessor of CIPA (Camera & Imaging Products Association). Today, JEITA  (Japan Electronics and Information Technology Industries Association) manages the standard, while CIPA discusses new technology and promotes the standard.

Although Exif data come primarily from digital cameras, some scanner drivers also write such information in the files they generate. Raw file processing software can use the Exif information to more accurately render the images, and new technologies, such as Exif 2.2 (also called “Exif Print”), incorporate this photographic information to help render a photographers' intentions in finished prints.

A fairly comprehensive list of the various attributes which can be stored in Exif (Exif Tags) can be found on Phil Harvey's ExifTool site.

History of the Exif standard

Source: Hiroshi Maeno, Canon Inc. June, 7, 2007, First International Photo Metadata Conference, Florence, Italy.

Official JEITA Website: http://www.jeita.or.jp/

Exif Print PDF on CIPA site: http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf

Unofficial Exif Website: http://www.exif.org/