Being a Canon fan I sadly have to add another strike against Canon that I recently came across and that has relevance for the scientific use of UWphotography. The latest TTL electronics, including the one implemented by the Canon 20D and most other "recent" cameras, get focus distance information from the lens to estimate the proper strobe power. There is a special tag in the EXIF header to write this distance information into, and many cameras do, but Canon DOESN'T, not even in the 30D and other more recent ones

I complained, and based on Googling many others have, but the powers that be have decided that it is not a priority or whatever their reason is to hide that information. With the distance and focal length you can calculate the magnification and I could write a program to include an optional size bar in the image or allow the user to click on two points and request the real-world length between those two points. It could of course also tell you if you are at 1x or 0.78x magnification. Pretty useful in my opinion, especially if you want to use your camera as a scientific data collection instrument. Alas, no such luck with Canon. Has anyone heard about a way around this or has anyone used this information with another brand of camera?
Bart