Has any-one here tried using wide-angle or tele adapters on their digicams?
I have a Dimage 7i and have tried a few different ones, mainly to get a 
"fisheye" effect.
What I've found is that at the widest zoom (28mm, 35mm equiv) I do get a 
nicely distorted image, but at least some vignetting around the edge of 
the image.

What are your experiences and has any-one found an ultra-wide adapter 
that doesn't give that black ring around the image?