JEITA CP-3451 Explication
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Explication of Exchangeable image file format for digital still cameras:
Exif Version 2.2
This document provides explanatory information on the latest revision to the Exif Standard, Version 2.2. This
document includes explanations referring to the definitions in the Exif Standard, reference material in relation to the
standard, and information in relation to the development of the standard. This document is entirely informative and
shall not be considered as an integral part of the Exif Standard.
1. Purpose of the Revised Edition
The digital still camera image file format standard, commonly referred to as Exif, is widely used as an international
standard for digital still cameras (DSC), and in many other fields in addition to DSC. Recent technology
advancements in both DSC resolution and print quality have brought demands for simpler, higher-quality printer
output. The revised Exif Standard addresses these needs by adding new tags to record information considered to
be useful for printer output processing, additional GPS information, and making other minor additions and changes
to the existing Exif Standard Version 2.1.
2. History of Revisions
Exif Standard Version 1.0 was issued on October 1995 as a standard of the then Japan Electronics Industry
Development Association (JEIDA). The most recent version, Exif Standard Version 2.1, was issued on July 1998
with additional tag information and recording format options. The DCF Standard, defining camera file system
standards to enable image files to be exchanged among different recording media, was standardized in December
1998 as a companion to the Exif Standard. The main features defined in each of the Exif Standard versions are
summarized below.
a) Exif Standard Version 1.0
Specification of image data format, tag information structure and basic tag
definitions.
b) Exif Standard Version 2.0
Addition of sRGB color space, compressed thumbnails, and audio files.
c) Exif Standard Version 2.1
Addition of interoperability tag.
d) DCF Standard Version 1.0
Specification of directory structure, file naming, and image playback scope.
Thereafter the Japan Electronics and Information Technology Industries Association (JEITA), formed by the merger
of JEIDA and the Electronic Industry Association of Japan (EIAJ), requested further deliberations by the Digital Still
Camera Committee, a DSC Format WG of the Japan Camera Industry Association (JCIA). The first meeting was
held on September 13, 2001 to determine the role, objectives and schedule of the committee. The committee
resolved to follow the basic design principle of previous Exif Standards, which was based on monitor-oriented
image quality design, though setting the primary objective of this revision to extended the tag definition to allow
information useful when processing to be recorded by a DSC for printer output. This was to improve the image
quality of printer output and other devices in addition to monitors. The committee further resolved to accept
proposals to add tag information that were not necessarily in scope of the primary objective when there was a
request. Given the strong desire to complete the revised standard at an early date, the timeline was set for