In a nutshell, a player's size shrinks in an inverse linear relationship between target distance and size in the scope. From 100 meters to 200 meters, a player appears half a size smaller in the reticle, but appears only 1/6th smaller from 200-300 meters.
The pattern is simple: relative to a player's size at 100 meters, a player's size is 1/2th at 200 meters, 1/3rd at 300 meters, 1/4th at 400 meters, 1/5th at 500 meters, 1/6th at 600 meters, 1/7th at 700 meters, 1/8th at 800 meters and so on.
What this means is that if you calibrate your field of view (FOV) such that the known height of a player at 100 meters or so extends from the tip of the thick bar in the upper half of the duplex reticle to the centre, you will be able to deduce a player's distance by interpreting their height as a fraction.
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| Def's DayZ Scope Overlay |
Try adjusting your FOV value in your playername.DayZProfile file to 1 (You can find this file in My Documents\DayZ). Note the position of the slider in the in-game FOV setting. It should be exactly on the right edge of the "d" in "Field".
A player should then be at around 100 meters as in the above image of the overlay. Note that when you decrease your field of view to the minimum, you double the magnification from 1 to 0.5. This means a player at 1/3rd size is now at 600 meters as opposed to 300.
