Can be used with 17mm wide angle lenses (35mm film) or 11mm on 20D/350D etc
Half the price of the similar spec Canon 580 EX flash
ETTL II compatible
Simple to use - easier than the super version
Great results, especially in ETTL mode

Large if you are not used to big flashes
Build quality is fine but not exceptionally solid

A very competent and affordable ETTL II compatible flash for Canon eos cameras. Quite a large product but attached to your eos camera looks like a pro piece of kit with enough power for most situations. I compared this with the Super version and found this ST version a lot easier to use. It can be used in ETTL mode for automatic flash which I found the best and in manual settings inculing 1/16th power for shooting in continuous rapid shooting photography. Best thing, it can be used on ultra wide lenses without vignetting.