Thanks for the reply lulu5, I tried every setting, with no effect. Sunba tech support was very quick, but ineffective- they sent me a new firmware, and suggested some settings. I tried them all, but without result. Apparently this camera does not have a manual exposure mode at night. During the day, the AE Reference setting did have an effect and I could make the image as dark as I wanted. Just not at night. The Sunba tech looked at the screen captures I sent and agreed the camera would not do what I wanted, and asked me to just return it, which I have now done. They said they would come out with a firmware update sometime in 2017 that would improve dynamic range, for what that's worth.