5
http://www.photometadata.org/META-Tutorials-Expression-Media
see also:
http://fotoforensics.com/tutorial-meta.php
You can also download this app for mac or windows:
http://www.sno.phy.queensu.ca/~phil/exiftool/
I uploaded a photo I took to the website below and it extracted all the metadata you see below:
All the below metadata can also be seen in Adobe Lightroom and other metadata viewers but the above site is free and gives you a good idea of how much info there is in side a photo you have taken.