Click the fine adjustment button that moves the focuser inwards
and click once. Observing the focuser knob on the opposite side to
the EAF note how many steps the EAF moved before the knob
moves. The number of times you click x 10 is the number of steps
measured as backlash.
Set the number of steps in the Set Backlash settings box
If you want to measure the backlash setting more accurately then
chose Step Size 5 in the fine step setting and repeat the above
steps.