
Top: 5D lens system. Bottom: 4D lens system.
As new lights are released, the labels '4D' and '5D' are mentioned a lot without much explanation. In this article, We're going to explain the benefits of each lens system.
All LED light bars use the same basic premise; a number of small LED chips placed in a row to light up an area. However, how efficiently the light is used is the key difference between light bars.
An led with no lens will have a light pattern that is very diffused and unfocused, which lights up a very wide area, but with a very weak light.
By adding a 5D or 4D lens system to a light, the lens acts as a kind of magnifying glass that projects light much further and wider.

4D lens systems contain 4D technology, which adds a fish-eye projector lens to each LED. This lens helps to simultaneously spread and focus the lights of the LEDs, which helps to illuminate far in front of your rig.
5D lens systems features a newer 5D technology that adds a reflective projector cup on top of each led, which spreads the light even more, giving you more total area illumination, as shown in the graphic below.

While it seems like a no-brainer, the 5D lenses also come with a higher price tag, often 20% more than 4D lenses. So if you are looking for quality, nothing beats a 5D light bar. However, if you are looking for a more economical choice, a 4D light works just fine.
So to sum it up:
4D Lenses:
Slightly older technology
Fish-eye lens helps to focus light farther out
More economical choice
5D Lenses:
Newer technology
Fish-eye lens + reflector cup provides wider illumination
More expensive choice
1 comment
I just fitted the H4 led bulbs to my BT_50. Well what a difference. In combination with the boss light bar night driving is a thing of the past. They light up the road like it is daylight. Thanks guy’s for great products at great prices.