The acceptance angle is the angle sustained by the objective lens, that filters out large-angle reflections. jems sets it to 200 [mrad] or ~250 [nm^-1] by default at 300 [kV]. It is changed using the control of (SAED pattern drawings). The value of this angle is used to limit the region of reciprocal space that is scanned to generate the reflections participating to diffraction. When it is not large enough, diffraction patterns may show a wrong symmetry (Fig. 1).

When the acceptance angle is not large enough some FOLZ reflections are missing (Fig. 1). In such a case a slight increase of the acceptance angle solves the problem (Fig. 2). Do not use a too large acceptance angle as the calculation time increases with increasing acceptance angles.