MakerNote

Exif tag 37500, "MakerNote", is (unfortunately) a popular way to store custom metadata, particularly in image files created by digital cameras (see Cameras and Digital Image Sensors).

By the Exif standard, MakerNote is merely a block of arbitrary bytes, which creators of Exif files may use in any way they like.

Some of the data formats used in MakerNotes have been documented or reverse-engineered. A MakerNote usually begins with a signature of some sort, such as the name of a camera manufacturer, to help identify its contents.

Software

 * ExifTool
 * Metadata++