High-Res HDRI Map Pack 2 . ab by smashmethod

The reason they are hemispheres is because they're faked maps generated from stock photos, they weren't shot in a spherical ball, they were processed off of stills and saved in .hdr format, because they generally do the same thing in the program. For most "realistic" scenes, you're going to have a ground plane / horizon line, and that ground plane will always cut off the black section below the hemisphere line. If you want, you can just open it in Photoshop, mirror the top half to the bottom half, and resave it. So long as your reflections aren't showing the map too clearly, no one should notice. Photoshop versions CS2 and up (I think) open and save .hdr files without an external plugin necessary.

ctrl+f "Download"

Oh also... I know these are HDRI images for reflection and lighting purposes.. but I really really like it as a 'backdrop'. When I render it as a still image, the background shows up, but when I batch render for animation, it's just a white screen. Anyway to use it as a background image too? I don't want to import in onto a poly sphere cause that will probably block the light. Any ideas?