You won't see "Flash Used - Yes" in the EXIF information because the 283 does not communicate very much with the 20D. Note: This is a "Made in China" 283 with safe trigger voltage. The older "Made in Japan" version has an unsafe trigger voltage but can be used with the Wein SafeSynch. Problem is the SafeSynch costs almost as much as a new flash. The 283 is not being sold any more. Update: I've recently moved on to a Sunpak 383 which is a highly respected unit, but I suspect I will move on to a flash with more functioning with Canon dslrs. Update: I bought TWO Canon 580ex units and couldn't be more happy with their automation. I can slave the 283 if I want another flash for multiple flash use (with the use of a little slave trigger).