Nice one millighost. My suggestion of root two was purely a guess since that factor seems to be implicated in so many other areas. I hadn't considered that the virtual camera would be using a one inch sensor. That makes perfect sense.

I expect you're right about Edward, since he laid down the legal definition of an inch as the length of "three grains of barley, dry and round, placed end to end, lengthwise". Although common usage of that measurement dated back to the Norman conquest, so as so often in English history we have to ask ourselves "what did William the Conqueror ever do for us?" :)