15mm fisheye can be a really great wide angle lens for cameras with high crop factor like Canon D30/60. When de-fished with Panorama Tool, it comes out as about 20mm rectilinear lens. ( http://www.acapixus.dk/photography/lenses_on_D30.htm And, the best thing is it's quite sharp. I've compared to Sigma 15-30/3.5-4.5, Tokina ATX-Pro 17/3.5, and Zenitar 16mm fisheye lenses, and my current Sigma was much sharper than all of these lenses on my D30.