Comments about ExpoImaging Expoimaging Ray Flash Adapter for Canon 580EX with Canon 1D, 1Ds, and 1V Cameras:
Great ring-flash results without the huge cost and bulk. I love this adapter.
It's a bit heavy however, and I worry about breaking the hot shoe foot on my flash with extended use.
The effect is every bit as good as my studio ring flash costing $2000.