Vincent Bockaert, 123di.com

Besides information about the pixels of the image, most cameras store additional information such as the date and time the image was taken, aperture, shutterspeed, ISO, and most other camera settings. These data, also known as "metadata" are stored in a "header". A common type of header is the EXIF (Exchangeable Image File) header. EXIF is a standard for storing information created by JEIDA (Japan Electronic Industry Development Association) to encourage interoperability between imaging devices. EXIF data are very useful because you do not need to worry about remembering the settings you used when taking the image. Later you can then analyze on your computer which camera settings created the best results, so you can learn from your experience.

Example of EXIF 2.2 information extracted with ACDSee 6.0.3 which allows the data preceded by the "pencil" icon to be edited.

Most current image editing and viewing programs are able to display, and even edit the EXIF data. Note that EXIF data may be lost when saving a file after editing. It's one of the many reasons you should always preserve your original image and use "Save As" after editing it.

This article is written by Vincent Bockaert,
author of The 123 of digital imaging Interactive Learning Suite
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