...here's a test render I made in Vue 5 when it first came out two years ago- the TOTAL illumination for this scene was a SINGLE white tile (240 x 240)!

Being LDR- the render is quite FAST!  It would be nice if Bryce 6 would allow this type of illumination source for IBL. I can only guess they (DAZ) haven't yet because they don't want to "confuse" people- and let them get a grasp on HDR first...

Needless to day, LDR doesn't have the Dynamic Range of HDR- but it (LDR) is a really FAST and a SIMPLE way to light a scene!...