Glossary: what is EXIF?

Besides information about the pixels of the picture itself, digital cameras store additional information:

• Date and time the image was taken
  
• Aperture
  
• Shutterspeed
  
• ISO
  
• Flash status
  
• Exposition program used (e.g., Portrait, Landscape, Macro)
  
• And most other camera settings
  

These data are known as "metadata" and they are stored in a "header" of the image. A common type of header is the EXIF (Exchangeable Image File) header. EXIF is a standard for storing information. It was created by JEIDA (Japan Electronic Industry Development Association) to encourage interoperability between the wide range of imaging devices. EXIF data can be very useful because you do not need to remember the settings you used when taking the image. Later you can use your computer and appropriate software to analyze which camera settings created the best results, so you can learn from your experience.

Most current image editors and viewers are able to display EXIF data, and some of those programs also allows editing EXIF data. Be aware that EXIF data may be lost when saving a file after editing in some program. It's one of the many reasons you should always preserve your original image file and use "Save As" command after editing it.

The example of free imaging software capable of viewing EXIF data is XnView. It is very powerfull image viewer with some image editing features. It's worth to download and use.