When your choices for a fisheye lens are cost-prohibitive (this lens would be nice), re-purposing a point-and-shoot becomes an attractive option. The Opteka .45x wide-angle adapter saves the day.
Below, Sigma 10mm fisheye for Canon SLR $699, Opteka .45x wide-angle adapter $29 (for Olympus C-8080, search for your particular camera model – there are numerous models supported) and a couple sample images taken with the Olympus/Opteka combo. On the cropped Canon body the Sigma comes out to 16mm actual focal length, the Olympus with 28mm x .45 comes to 12.6 (call it 13) mm. Also, don’t overlook the macro capability, this adapter allows some VERY close focusing. See below images for the caveat.
Sigma 10mm Fisheye
Opteka .45x Wide-angle Adapter (For Olympus C-8080)
Duluth Lift Bridge
Duluth Lift Bridge
Duluth Harbor From Enger Tower Park
One limitation of this adapter, at least on my C-8080, is that when using it at full wide angle (which is where you want to use it 99.9999% of the time), the image sensor sees the edges of the adapter, making cropping or extreme vignetting necessary. Do note though that the above image is cropped to 3:2 aspect, whereas the following images are the native 4:3. There is also some significant chromatic aberration added. I use these settings in Lightroom to compensate:
Chromatic Aberration Adjustment in Lightroom
Uncropped Wide Angle Image
Using vignetting to hide the adapter edges
Centerpiece Close-Up
The Daaaawwwwg