Your link provides all of the decoding information.  I'm not sure what else you want.  The first byte is the ISO, converted by the formula provided (val = 100 * 2**(raw/12-5)).  I don't know what the next 3 bytes are for (01 0c 00).  Then 2 bytes for ISOExpansion, etc... Thank you very much for the quick reply. I want to know how these numbers relate to the ISO, that was all. I am just starting out in Software Development and have been given a camera issue to solve which involves working out these numbers. Is there any chance you would be able to use one of the numbers (e.g. 48 for 200 ISO) in that formula provided so I can see how you're using it as I don't understand the formula.