I have extracted the metadata from an image. One of the values was:
FocalLength: (3680, 1000)
How can we read the above value?
Values in Exif metadata can be stored as various data types, including ASCII text strings, "short" or "long" integers, or "rationals". A short integer is stored in two bytes; a long integer takes four bytes. A "rational" is:
Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator.
FocalLength: (3680, 1000) means 3680 / 1000, or 3.68. (Elsewhere in the spec, this is defined to be in millimeters.) For whatever reason, whatever program you are looking at this with is just showing you the two "long" values rather than doing the math for you.
It's also incredibly important to note that hundredths of a millimeter is almost certainly excess precision. For practical use, call this 3.7mm or 4mm.