How to create a photo with distortion? which lens? (images included)

[UUilliam]

Okay I really LOVE this type of photography, MY Canon 18-55mm has become my new best friend (well the 18mm side anyway)
really love capturing the distortions but I want to "upgrade"

So what lens would I need to create images like;
Kimmeridge Washing Ledge on Flickr - Photo Sharing!
Seascape @ Rancho Palos Verdes on Flickr - Photo Sharing!
Gunwalloe Sea Mist on Flickr - Photo Sharing!


I am guessing a 10-20mm Sigma would be the best choice for this sort of Photographing?

 

[Hobbes]

Well if you check the exif data of one of the images the photographer did use one of those 10-20 something mm lenses.

I have a Sigma 10-20 and it's a great landscape lens even though it's really soft wide open but I almost never go lower than f/8 when I shoot landscapes. I think the best equipment for those kind of photos would be a combination of a full frame camera and a sigma 12-24mm