When you're shooting for a truly exaggerated point of view & twist on the Century Fisheye Adapter. The Fisheye gets you a wide view & with a non-vignetting fisheye look.
The fisheye exaggerates depth & pulling nearby objects closer & and causing distant objects to recede into the background.
A fixed adapter & the Fisheye doesn't allow for zooming — but you'll want to stay at the wide end of the range anyway & for the most pronounced effect.
Angle of View
zoom in auto focus only