'jhead' is a program to parse through the little file system in the Exif
headers and extract digital camera settings.

Information that the 'jhead' program can extract from an Exif file:

	Integral low-res Exif thumbnail 
	Shutter speed 
	Camera F-stop number 
	Flash used (yes/no) 
	Focus distance (some digital cameras store this element) 
	Focal length (most zoom cameras store their zoomed-to focal length) 
	Equivalent 35mm focal length (Calculated from focal length, CCD
	 size, and CCD resolution) 
	Image resolution 
	Time and date picture was taken 
	Camera make and model 

WWW: http://www.sentex.net/~mwandel/jhead/