Lighting Behaviour
Beam Angles
The beam angle decides where the light lands and how hard it reads. It is the most consequential choice on the spec sheet — and the one most often left to whatever fixture happened to be in the box.
What a beam angle actually describes
Every fixture throws light in a cone. The beam angle is the width of that cone — the angle across which the fixture delivers at least half of its peak intensity.
A narrow beam concentrates output into a tight column. A wide beam spreads the same output over a larger area, which means lower intensity at any single point. Same lumens, very different result.
Two numbers matter. The beam angle is the cone of useful, bright light. The field angle is the wider cone where light fades to roughly a tenth of peak — the soft edge. When we specify a fixture we choose the beam angle to suit the target and accept the field spill as the transition into shadow.
The three working bands
Most residential landscape lighting is covered by three ranges. Choosing between them is the first decision on any fixture.
Narrow — 10° to 18°
A tight, intense column. Used for tall trees, columnar planting, and grazing a textured wall from close range. Narrow beams hold their intensity over distance, which makes them the only sensible choice for a canopy eight to twelve metres up.
Medium — 24° to 40°
The general-purpose band. Suits medium trees, shrub masses, and feature planting where you want to read structure without a hard spotlight effect. If you are unsure, a 30° beam is rarely wrong.
Wide — 45° and above
A soft wash. Used for low hedging, garden beds, and even facade coverage from a short setback. Wide beams lose intensity quickly with distance, so they belong close to the target.
Beam angle and distance work together
A beam angle is not a fixed pool of light. The further a fixture sits from its target, the wider the cone has spread by the time it arrives — and the dimmer it has become. As a rule, doubling the distance roughly doubles the spread and quarters the intensity.
The practical consequence: a beam that looks right at three metres is twice as wide and a quarter as bright at six. Plan the beam around the real throw, not the fixture in your hand.
| Throw distance | 15° | 30° | 60° |
|---|---|---|---|
| 3 m | 0.8 m | 1.6 m | 3.5 m |
| 6 m | 1.6 m | 3.2 m | 6.9 m |
| 9 m | 2.4 m | 4.8 m | 10.4 m |
Approximate beam spread (diameter) at the target. Field spill extends beyond these figures.
Matching the beam to the task
- Tall trees, six metres and up: narrow, 10° to 18°, positioned to send a column up the trunk into the canopy.
- Medium trees and large shrubs: medium, 24° to 40°, offset from the trunk to model the form.
- Hedging, mass planting, and low beds: wide, 45° and over, mounted close.
- Wall grazing for texture: narrow, mounted tight to the wall to rake light across stone or render.
- Wall washing for even coverage: wide, set back from the wall to flatten the light.
Grazing and washing are opposites that use the same wall. Grazing sits close with a narrow beam to exaggerate texture through shadow. Washing sits back with a wide beam to erase shadow and deliver flat, even light. Decide which effect you want before you choose the fixture.
LUMINI rule of thumb
Choose the beam by the height of the target first, the distance second, and the wattage last. A correctly aimed narrow beam at low output beats an over-driven wide beam every time.
Where it goes wrong
- One beam angle for the whole garden. A single fixture cannot light a ten-metre gum and a 400mm hedge.
- Wide beams at distance. The light arrives weak and washes everything flat.
- More wattage to compensate for the wrong beam. The fix is a tighter beam, not more lumens.
- Ignoring growth. A tree can double in height over a decade — the beam that suits it now may not in five years.
Related
Planning a scheme?
Send us your plans or a few site photos. We will recommend fixtures, beam angles, and transformer sizing for the project — no formal brief required.
Start a project enquiry →