Definition: EXIF (Exchangeable Image File Format)

Definition: EXIF (Exchangeable Image File Format)  | Glossary entry

EXIF (Exchangeable Image File Format)

Image files are really data files. Most of the data tells the computer how to display the image on your screen.

Image files have additional metadata which provides details about the image file. Known as EXIF data (Exchangeable Image File Format), this metadata is particularly important. EXIF data is a standard recognised by camera manufacturers as the way to store metadata about the image file.

EXIF data describes features of the image itself and its creation. It includes the following types of data…

  • The image file itself (eg. file name; image width; image length; file compression type (JPG, tiff etc); picture orientation; resolution; resolution units (inches, cm etc); date created; EXIF version…)
  • The camera/lens data (camera make; model, version, serial number, makers notes…)
  • Data about the image (exposure time; f/number; exposure program (aperture priority, manual etc); ISO rating; shutter speed value; exposure bias value; metering mode; flash setting; focal length; user comments; color space; custom settings, exposure mode; white balance; capture mode…)
  • Personal data (author; location; contact…)
  • Copyright data (copyright owner; copyright conditions etc…)

The Field types listed above are not exclusive. Any particular EXIF data in a file will depend on what the digital camera is programmed to collect. This will vary between models and manufacturers.

Other types of metadata formats beside the EXIF data may be stored in image files. For example IPTC data.

EXIF data fields are defined by the EXIF standard. There is room for interpretation about what goes into each field. And, individual camera companies have ranges of fields for their own use. There are many hundreds of fields. More detailed information on the structure and format of the known EXIF data can be found here…
EXIF Tag list External link - opens new tab/page.
Individual manufacturers also have their own tag lists relating to the specific EXIF data for their use. These are the tags which identify the exposure data among other things. The tag lists for two manufacturers are included below. The rest can be found listed in the ‘MakerNote’ section of the EXIF Tag list External link - opens new tab/page (the general EXIF schema).
Canon EXIF tag list External link - opens new tab/page
Nikon EXIF tag list External link - opens new tab/page

The EXIF standard is supported in most image files that relate to image creating equipment including JPEG/JPG, Tiff, RIFF and WAV. It also includes the ‘RAW’ file format from the major camera manufacturers. However, some image files do not support the standard. These include: JPEG2000, PNG and GIF.

The following manufacturers are known to have EXIF tag spaces reserved for their use in the EXIF schema…

Canon, Casio, FujiFilm, GE, Hasselblad, 
Hewlett Packard, ISL, JVC, Kyocera, Minolta, Nikon, 
Olympus, Leica, Panasonic, Pentax, PhaseOne, 
Reconyx, Ricoh, Samsung, Sanyo, Sigma, Sony

How much use manufacturers make of EXIF data varies. You should consult the EXIF data in your images to find out what is available.

Exif data can be edited and additional data added. A range of applications are available which allow users to access the data and edit it in a file. Simple edits can also be done in Windows, Mac OS X and various other operating systems. More information on accessing and editing EXIF data can be found here… EXIF Data – Understanding Your Shots

There is an example EXIF data set after the link list.

Example EXIF data

The EXIF data below has been extracted from an image taken on a Canon camera. Not all the tags in the schema are available for use by the camera. Different tags/information might be provided by an other brand of camera.

Filename - IMG_0010.CR2
ImageWidth - 5616
ImageLength - 3744
BitsPerSample - 8 8 8 
Compression - 6 (JPG)
Make - Canon
Model - Canon EOS 5D Mark II
StripOffset - 62172
Orientation - Left bottom
StripByteCount - 1488300
XResolution - 72
YResolution - 72
ResolutionUnit - Inch
DateTime - 2012:06:09 10:08:49
Artist - Photographer: Damon Guy - Photokonnexion
Copyright - Copyright: Damon Guy [The Author]
ExifOffset - 434
ExposureTime - 1/250 seconds
FNumber - 8
ExposureProgram - Manual control
ISOSpeedRatings - 400
ExifVersion - 0221
DateTimeOriginal - 2012:06:09 10:08:49
DateTimeDigitized - 2012:06:09 10:08:49
ComponentsConfiguration - YCbCr
ShutterSpeedValue - 1/256 seconds
ApertureValue - F 8.00
ExposureBiasValue - 0
MeteringMode - Multi-segment
Flash - Flash not fired, compulsory flash mode
FocalLength - 70 mm
UserComment - 
SubsecTime - 55
SubsecTimeOriginal - 55
SubsecTimeDigitized - 55
FlashPixVersion - 0100
ColorSpace - sRGB
ExifImageWidth - 5616
ExifImageHeight - 3744
InteroperabilityOffset - 42296
FocalPlaneXResolution - 3849.21
FocalPlaneYResolution - 3908.14
FocalPlaneResolutionUnit - Inch
CustomRendered - Normal process
ExposureMode - Manual
White Balance - Manual
SceneCaptureType - Standard

GPS information: - 
GPSVersionID - 2.2.0.0

Maker Note (Vendor): - 
Macro mode - Normal
Self timer - Off
Quality - RAW
Flash mode - Not fired
Sequence mode - Continous
Focus mode - AI Servo
Image size - Large
Easy shooting mode - Manual
Digital zoom - None
Contrast - Normal
Saturation - Normal
Sharpness - Low , -32769
ISO Value - 32767
Metering mode - Evaluative
Focus type - Auto
AF point selected - 
Exposure mode - Manual
Focal length - 70 - 200 mm (1 mm)
Flash activity - Not fired
Flash details - 
Focus mode 2 - 65535
Auto ISO - 100
Base ISO - 400
White Balance - Cloudy
Sequence number - 0
Flash bias - 0 EV
Subject Distance - 0.00
Image Type - Canon EOS 5D Mark II
Firmware Version - Firmware Version 1.1.0
Owner Name - Damon Guy - Netkonnexion
Camera Serial Number - 1030710662 (3D6F25990)
Sharpness (EOS 1D) - 18
Directory index (EOS 450D) - 0
File index (EOS 450D) - 426
File number - 000 - 0000
Sharpness (A0) - 3

Thumbnail: - 
JpegIFOffset - 44448
JpegIFByteCount - 17723

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