Creating HDRI files

Is it possible to create an HDRI file without using a reflective sphere? Also, is there any free software to compose HDRI files?

An elysiun search turned up no relevant information that I could find, and a google search just turned up commercial HDRI programs.

use hdr shop http://www.ict.usc.edu/graphics/HDRShop/download/

as to your question with mirrord balls, yeah you do need to use them, it’s really the only way,(you could also do it by taking an up, down, left, right, front, back pic, however the pics need to be orthogonal, and i think that pretty much impossible to do in the reall world

hope this helps