Hi Rodrigo, Thanks for the reply! Yes, I adjusted the ISO. The problem was in fact that the brightness of the resulting image was changing strangely according to the zoom level - more zoom-dark, less zoom bright. This was happening even with just sky in the view port... However, the units of my file were set to millimeters. Once changed to meters, everything is apparently fixed. Maybe Light cache or another setting that takes distance into account was the cause.