Neepneep: Thanks for the tip. I'm no Sketchup man right now but I might as well give it a shot. I actually find camera matching alright in Blender. The problem is getting all the info you need about the camera length.
Kwistenbiebel: Glad you think so too. But there are a few interesting features coming up soon in Fryrender, I'm told

Jurasek: Hi mate. Yes, it's all lit by emitter. I'm pasting the camera settings. I used camera tonemapping. This is for one of the two images I merged. The second one had aperture diffraction on. But it seems to slow down high-resolution renders a lot. It takes forever for the filter to apply, which is why I cut it short. Not the same when working with smaller images