Data Storage and File Formats on Digital Cameras

Exif, or Exchangeable image file format, was designed by JEIDA, the Japan Electronic Industry Development Association.

It uses the existing JPEG, TIFF Rev. 6.0, and RIFF Wave file formats, which are the standard methods of compression for digital photography. They additionally use metadata tags which have caused some discussion as to their usefulness. JPEG 2000 and PNG do not support this technology.

TIFF files provide the Exif tags' structure, and there is a great deal of overlap between the standards of the tags in TIFF, Exif, TIFF/EP, and DCF. A broad range of metadata tags appear in the Exif standard:

* Current date and time recorded on the photos are part of this information.

* Information such as the make and model of the camera.

* Orientation, aperture, focal length, film speed, shutter speed, and metering mode are included, even though they vary with each image.

* Thumbnail prints allow immediate viewing of the picture on the LCD screen.

* A few cameras support a GPS receiver.

* Copyright information and descriptions are available on higher-end cameras.

Most of the older programs do not recognize Exif date, which is embedded within the image file, while many of the recent programs recognize it and will retain the majority of it when writing to a modified image. Some recognize it and display it beside the images.

File formats are one way of recording information for storage in digital cameras; it specifies the use of TIFF or JPEG. TIFF is the highest quality, and JPEG is used to save space at the cost of quality. JPEG is the only format available in many of the less expensive digital cameras.

CCD-RAW is another format you may encounter; the data is processed minimally and must be converted to TIFF or JPRG in order to be edited. This format is not standard.