Two floodlights with the same wattage and the same lumen may produce completely different effects on the spot. The difference lies in the light distribution. Beam angle, installation height and projection angle together determine coverage area, uniformity and glare.

The illuminated diameter is approximately equal to "installation height × 2 × tan(half beam angle)". The 30° floodlight on the 6-meter pole has a spot diameter of about 3.2 meters; the same height is changed to 120°, which can reach nearly 21 meters. There is no advantage or disadvantage between the two in themselves-the narrow beam concentrates light where it is needed, and the wide beam spreads an area evenly. The wrong choice is the root cause of "bright spots under the lights and blackening on the edge of the venue."

When the target surface is rectangular rather than circular-a stadium, building facades, perimeter walls-asymmetric light distribution is often the better answer. It "pushes" the light distribution away from the direction of the pole and covers the entire plane, which not only improves uniformity, but also reduces wasted light thrown upward. At present, many European projects have required manufacturers to provide upward light flux ratio data, because light spilled into the sky is both a waste of energy and a compliance issue in some cities.

Glare deserves the same attention as coverage area. Mounting high-power floodlights in a low position and shooting straight into the human eye is unfriendly to anyone who approaches. Before finalizing the lamp layout plan, first confirm whether the lamp has an anti-glare hood or a shielded light distribution plan.