There are 6 well known radiance map images created by Greg Ward. Five of them are available in HDR and one in HDR and OpenEXR file formats. Moreover there are 9 light probe images available in HDR file format.
Dataset of Greg Ward’s radiance maps with preview of tone mapped images is available at: Link: http://www.pauldebevec.com/Research/HDR/ Light probe images are available at: Link: http://www.pauldebevec.com/Probes/
References and Citation
The reference for the paper that produced these images is [DM97] for Grag Ward’s images and [Dev98] for light probe images.
DM97: Paul E. Debevec and Jitendra Malik. Recovering High Dynamic Range Radiance Maps from Photographs. In SIGGRAPH 97, August 1997.
Dev98: Paul Debevec. Rendering Synthetic Objects Into Real Scenes: Bridging Traditional and Image-Based Graphics With Global Illumination and High Dynamic Range Photography, Proceedings of SIGGRAPH 98, pp. 189-198 (July 1998, Orlando, Florida).