From a member in chat:
Here at my office I have a Hik-2CD2942F-IS Fisheye 4m lens. Instead of doing a horizontal mount on the ceiling we are doing a vertical mount on the wall. My question is what is the optimal height to put this fisheye on the wall where I will be able to see most of the room Verses lets say just only able to see everyones neck and head or to low where we would only see someones pants and no higher.
I was thinking 13 Feet, but I may be thinking to high and I do not wish to drill holes in the wall unless I am sure it will be ok.