That is exactly what ghostship2 is suggesting. A high-quality 360-degree panorama HDR provides a natural realistic lighting condition. That is what Snarly's EZDome provides, using a two-dome setup, one dome providing illumination and the other dome providing a background image. ATM, the image nodes in P12 are broken, they cannot project a background nor scene illumination. Until that is repaired, EXR files will have to do except not everyone have the software to convert HDRI to EXR.