What flash should I get?

[scraggles]

I'm not sure of which flash I should get, I don't fully understand the difference of them yet. I'm looking at anything from the 220EX to the 580EX. Price isn't an issue.

If someone could explain what the use of the different lenses are, that would be helpful.

[emidyl]

If money isn't an issue and you would like to take advantage of Canon's compatiblity than I would say 580EX.
It is more power than the 430EX of course but also will work with the ETTL-II technology.

[gugu]

If price isn't an issue the only reason not to buy the 580ex is it's size.
for me size is not a problem.

[scraggles]

It'll be compatible with my XT and suitable for the 17-40mm?

[gugu]

yes

[bolantej]

I have the 420EX and wish I had the 580EX for manual controls. It depends on what you want to do with it.

[lostdoggy]

If money isn't an issue and you would like to take advantage of Canon's compatiblity than I would say 580EX.
It is more power than the 430EX of course but also will work with the ETTL-II technology.

ETTL-II is feature of the camera not the flash. You can use any ETTL compatible flash w/ any ETTL-II capable camera and make use of the ETTL-II feature. I believe it has to do w/ distance measurement.

[Hank2122]

keep in mind the 430ex is lighter than the 580ex