BBB Cycling Australia - Light Guide 2018

LUX AND LUMEN
One of the most heard arguments
when buying a new light is: “I want
the most lumen possible.” But what
does the amount of lumen actually say
about the power or the usability of a
light? Because, every manufacturer
can produce a light with an enormous
amount of lumen. What makes
the difference?
First we have to explain the difference
between two concepts: lux and lumen.
Lux is the amount of light on a certain
area. Most commonly, it is measured
on a distance of 1 or 10 meters. When
the amount of lux is measured, a brand
wants the highest level and with a
round bundle, that’s in the middle.
Lumen is the total amount of light (in
all directions) emitted by that lamp.
This can be produced by the LED or the
lamp itself. The level of lumen from the
lamp itself is lower, because the light
has passed the lens, resulting in loss
of light. This is the most honest value,
because this is the amount of light you
really see in front of your bike.
The light always has to pass the lens,
obviously.
That’s why BBB always measures the
amount of lumen of the light and not
of the LED alone. Because that’s not an
honest value on itself.
STRIKE 300
BLS-71
How does this look like in
real development life?
Let’s take a look at the Strike lights
in our range. When we developed the
Strike 300 and 500 we didn’t want to
just boost the amount of lumen.
We wanted to create two worthy lights
on their own. Below you can see the
differences between the Strike 300 and
Strike 500.
Both lights produce 28 lux on a distance
of 10 meters. So they are evenly
‘bright’.
But the Strike 500 has 200 lumen more
light compared to his little brother. The
Strike 500 has a broader bundle as well,
resulting in 200 lumen divided over a
bigger bundle.
Why didn’t we choose to use the same
lens for both lights? That’s because
the human eye adapts to light. When
there’s a lot of light, the pupil becomes
smaller. With less light, the pupil
becomes bigger.
With a narrow bundle that’s very bright,
the pupil becomes smaller, resulting
in everything outside of your bundle
becoming ‘invisible’. Because it’s
outside the reach of your small pupil.
A logic question now would be to ask if
every light than has to produce 28 lux
on a distance of 10 meters. But that’s
not the case.
STRIKE 500
BLS-72
The keyword in developing lights
is ‘balance’. As a designer of these
products you constantly have to keep
in mind that the light has to match the
needs of each user.
A helmet light has to create more of a
hotspot, while a light on your handlebar
has to have a wider bundle. And a
light used on the road has to be about
visibility. Each light has its own specific
needs and goals.
SHAPING THE BUNDLE
There are three ways to shape the
bundle of light. We can use the classic
reflector, a lens and a modern reflector.
Classic reflector
With a classic reflector there’s not so
much control over the light. Basically,
the LED directly shines to the outside,
only the light that shines to the sides
is being affected by the mirror. This
produces a lot of rings in the bundle
and a bright hotspot, also called the
‘center’. This type of reflection is
only used in the low end range of the
market.
Lens
The best way to create a round bundle
is to use a lens. The main advantage
of lenses is that all the light from a
LED can be controlled. This creates a
beautiful grading or an extremely bright
hotspot.
Modern reflector
When using a modern reflector, the LED
is horizontally placed, shining directly
on the mirror.
This way there’s maximum control over
the bundle. Mainly lights which are
StVZO approved has to be developed in
this way, because of the complex bundle
that has to be produced. The main
disadvantage is the loss of a lot of light
when using this type of reflector.
The Swat BLS-105K has a bundle right
in front of the wheel and one further
in front of the rider. The bundle in
the distance is broad and the amount
of light is as equally divided over the
bundle as possible.
This way we created a functional
bundle, but the amount of lumen and
lux is not comparable with a round
bundle.
On the next page is an example of the
Swat light.
classic reflector
lens
LIGHTS EXPLAINED
LIGHTS GUIDE
300 LUMEN
28 LUX AT 10 METER
60° BEAM ANGLE
13° HOT SPOT ANGLE
500 LUMEN
28 LUX AT 10 METER
90° BEAM ANGLE
20° HOT SPOT ANGLE
Taking a closer look at one of the lights
from our range with a modern reflector,
we can see clearly two bundles.
modern reflector
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