External flash for 10D

[JAB1]

I need advice...can some of you advise me of a good external flash for the 10D?....I cannot use my 17-40 lens without a shadow at the bottom...should I get the 550Ex or another make/model?....thanks

[Vegas Poboy]

Depends on what type of shooting you do. If you're a semipro and up go for the 550ex you can adjust the flash in multiple settings. If you only plan on point & shoot get the 420EX but you can only adjust the flash + or - within the camera settings.
When you use the Canon Flashes there is the option to add on & there is least likely to have any commuinication problems between the camera & flash.
Within the last week or two there is a posting on the Sigma / Canon flashes I could'nt find it.