Please see Solution 10) at the top of this thread.I noticed something weird with emissive material. Preview render shows bright light, and final render - totally no light at all... I used pathtracing. I also used that kind of emissive material. By the way, wattage if that light seems way out of range, in the preview this is about 6W bulb. But even 100W emission won't show anything on final render.
I'm sorry, but I have not seen this problem before, and had no other reports of it. I would suggest trying Solution 3) at the top of this thread.Second thing is the weird camera resolution behavior - where did Octane plugin get this 4 x 4 pixels resolution from? It's really hard to workaround (playing around with every parameter I outlined on screenshot), and it's usually coming back after a while, like just now...
Resolution problem seems to apply only to preview rendering, final rendering seems to take one of these camera parameters and use it. It seems to happen, when there's either camera with its own resolution, or because I first remade a couple of shaders in a scene (emissive surfaces aren't converted from Iray at all and there's still glass-water-like conversion issues, so that needed to be fixed by hand) and after that I pressed "Open viewport" button.
Thanks
Paul