Beam angle is the angle between the two directions where luminous intensity falls to 50% of the maximum intensity at the center of the beam. A smaller beam angle concentrates light; a larger angle covers a wider area. Nordic Lights distinguishes beam angle from field angle, which is measured at 10% of maximum intensity. Because manufacturers may publish different angles or use different test conventions, the measurement point should be checked when products are compared. Beam angle describes only part of the light distribution: two lamps with the same angle can still differ in intensity, uniformity, field angle, and stray light. Photometric data provides a more complete picture.