Apeman M4 Manual Del Usuario página 14

Adjusting the Projection Image
Place your M4 Projector on a flat level surface at the optimal
distance from the screen or wall and move it horizontally.
See the picture below. The result of this calculation tells you
roughly how far back the projector should be positioned from the
screen in order to project a focused image large enough to fill the
screen. Recommended projecting distance is 0.8-2.6 meters.
100"
50"
30"
260cm
130cm
80cm
10