nope thats not what ML does with the HDR function
its just an easier way to shoot a series of pictures which you have to edit as usual with the software you have.
ML HDR lets you decide what kind of exposure steps you want and what kind of aperture.
I use ISO 100, in most situations shooting in AV mode is enough, but if you're expecting exposure times longer than your camera can do (my 550d can expose 30 seconds max) you might switch to Bulb mode. I dont know the 5D so maybe theres an extra mode for it.
in HDR AUTO mode, ML then decides how many pictures should be taken and how long the exposure has to be. mostly it works good, there's at least one very overexposed shot when its done, usually the last one, sometimes I don't use it beceause you can't see any details.
its a way quicker way than setting up your camera for bracketing by hand + it enables automaticly the 2 second trigger timer which you would also have to activate by yourself.
I dont use Canon bracketing anymore.
For preview you can hold the SET button in playmode and use the wheel to join the pictures together for a kind of HDR preview but thats just nice to have. (read manual)
thats a HDR I made without thinking alot, turned out quite nice I guess. had to drop the car with photoshop because it sits on stock springs
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/412475_10151052321904648_1956608954_o.jpgIf you're looking for ML making your pics an HDR by itself, I have to disapoint you....but its up to you how you think your HDR should look like, isnt it ? ;-)