Hello, my level of photography is intermediate and is a hobby (ie, family gatherings, events, etc) I shoot with a Canon 50D and use my Dads old Canon 199A as a flash with a diffuser set up manually and works great but I think its time to upgrade to something better that will work better with my camera. I don't really use the bounce feature but like to defuse the light when shooting so any of the 3 will probably do a better job than the 199A so so power isn't an issue there. I have a few questions: 1. I can pick up a 580EX on Ebay pretty cheap and it's more powerful than the 430EX II but will all the functions work with my camera? 2. Has anyone used the 580EX with a 50D? 3. Will either of the flashes change the amount of light it outputs when I zoom in and out? 4. Will the flash do the light metering or will the camera with the 580EX and 50D setup? 2. Will the flash do the light metering or will the camera with the 430EX II and 50D setup? 5. What are the major and minor differences between the 580EX and 430EX II and 580EX II? 6. I would go with the 580EX II new but it is a bit pricey and i am on a budget. Is it worth trying to pick one up used or save some $$$ and go with the 580EX or 430EX II? HELP! I'M SO CONFUSED!