The law of inverse squares
http://hyperphysics.phy-astr.gsu.edu...sion/isql.html
You dont need any more than 24 FPS and 18 FPS will do
There has been tons of info on this in FS forums
Have a look at the attached viewing distance graph
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Edit
This is worth having a look at
http://immersaview.com/servicesandtechnology.html
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