Optics and light distribution: putting light where it is needed

Light distribution describes the directions in which a luminaire emits light. Narrow optics concentrate it on a limited area; wider distributions cover larger surfaces. Asymmetric optics favour a particular direction, such as a wall or aisle. A luminous intensity distribution curve makes these differences visible.

Beam angle alone does not replace a lighting calculation. Mounting height, spacing and orientation determine where the light arrives. Tall warehouses and low offices need different solutions. Shelving, machinery and partitions may shade useful surfaces even where floor illumination looks adequate.

Reliable calculations require the photometric data of the actual luminaire variant, for example an LDT or IES file. A similar housing does not demonstrate equivalent lighting. Select optics, output and mounting positions together and compare results on the relevant working planes, including vertical surfaces where needed.

What to clarify for your project

• Record mounting heights, spacing and obstructions.
• Use photometric data for the exact variant.
• Assess working planes and vertical surfaces separately.

Remember: The right optic suits the geometry and task; maximum light output is not the only criterion.