The EXIF data
Posted by reedcat | Posted in Articles, Uncategorized | Posted on 18-03-2007
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Exchangeable image file format (official abbreviation Exif, not EXIF) is a specification for the image file format used by digital cameras. The specification uses the existing JPEG, TIFF Rev. 6.0, and RIFF WAVE file formats, with the addition of specific metadata tags. It is not supported in JPEG 2000 or PNG.
The Exif tag structure is taken from that of TIFF files. There is a large overlap between the tags defined in the TIFF, Exif, TIFF/EP and DCF standards.
The metadata tags defined in the Exif standard cover a broad spectrum including:
- 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, aperture, shutter speed, focal length, metering mode, and film speed information.
- A thumbnail for previewing the picture on the camera's LCD screen, in file managers or photo manipulation software.
- Descriptions and copyright information. Again this is something which is most often done when post-processing the images, as only high-end camera models let the user choose a text for these fields. (Although this feature is becoming more and more apparent even in lower end compact digital cameras).