The dragon is from the Stanford Scanning Repository. I prepared the HDRI used from the DVD that comes with the HDRI Handbook 2 by Christian Block for Bryce. The text that is only partly visible at left reads "Tokyo Big Sight". The HDRI is low to medium resolution and the experiment here was to match DOF for the objects and DOF of the HDRI backdrop. This isn't as straightforward because the backdrop is 2D and always at the same distance, no matter how near or far things are in the image. Renders with soft IBL shadows and DOF in 7-1/2 hours.