Pencil beam
A pencil beam refers to a particularly tightly focused light distribution in a high beam. The light is concentrated onto a comparatively narrow area, thereby achieving a high luminous intensity in the main beam direction.
Pencil beams are used in particular where a long range is more important than wide illumination.
Pencil beam as a high beam
In the case of headlights, a pencil beam can be designed as a particularly narrowly focused variant of the high beam. Compared to a wider high-beam distribution, a larger proportion of the available light is concentrated within a small angular range. This allows areas further away to be illuminated more brightly, whilst the lateral illumination is reduced.
Further typical beam patterns are shown in the article beam patterns of headlights.
Luminous flux and range
A high luminous flux in lumens does not automatically mean a long range. How strongly the light is focused in the desired direction is also crucial. The luminous intensity in candelas is therefore particularly relevant to the range of a pencil beam. Two lights with the same luminous flux can achieve significantly different ranges due to different light distributions.