Canon 5D3 vs. Nikon D7000 LV help.

Need help please if you have the same cameras or any idea of why...
I shoot a Canon 5D Mark III and my daughter has a Nikon D7000. Last night we went shooting at around 9pm and cameras side by side, while my LV displayed a bright/luminous image, the Nikon's LV was much darker. The settings were changed on the Nikon but never came close to my LV display. In our case looks like Canon is amplifying the surrounding light in the night better than Nikon does. The dark sky looked a lot brighter with a lot of details of the image while Nikon was like having a ND filter on it (not the case). Is this a normal/common difference between the cameras or we did not setup the Nikon right? Need help please. Ask as many questions if it helps, want to fix this problem. Thanks.

What lenses were you both using?

Canon - Zeiss 50/1.4
Nikon - NikKor 24-85/3.5
Both cameras were set to ISO 100, f5.6, 20"
If it helps, tonight we will go out again, set the cameras side by side with the same settings on LV and take a picture of the back of the cameras.

Does live view use your settings for it's preview? I suspect that yours was brighter because your lens is several stops faster.

Both cameras were set to f5.6. Tonight will try with a 50mm on the NIkon, same as on my Canon.
Other than that, both cameras were set the same. I am puzzled...

Canon has "Exposure Simulation" which adjusts what you see in LV. I might be wrong but I don't think that Nikon has anything similar. I have always read that Nikon's LV implementation is not as good as Canon's.