How do you measure light beam angle?
Calculation:
- Required Lux at Surface (E2) =1390 Lux.
- Distance between Lighting Fixture and Surface (D) = 3 Meter.
- Fixture Beam Angle (ϕ)= 10°
- Solid Angle of The Lamp (Ω) =2xπx(1-COS(ϕ/2))
- Solid Angle of The Lamp (Ω) =2×3.14x(1-COS(10/2)) =6.28x(1-0.996)
- Solid Angle of the Lamp (Ω) =0.0239 Steradian.
What does beam angle mean?

The beam angle of a lamp is the angle at which the light is distributed or emitted. Lamps such as Halogens (and some LEDs) come in a variety of angles from, 4 degree to 60 degree with some of the larger halogen lamps up to 120 degree.
What is a 40 degree beam angle?
The standard beam angle (if there is such a thing) is 40 degrees. This is a medium spread beam that offers a good combination of intensity and coverage.
What is a 60 degree beam angle?
The beam angle of 60 degrees is perfect for use in the living room. It is also known as floodlighting and suitable for standard ceiling heights.

How wide is 60 degrees?
5.4 feet
What is Beam Spread?
Degree of Light | At 5 Feet | At 15 Feet |
---|---|---|
40 | 3.6 feet | 10.8 feet |
45 | 4.05 feet | 12.15 feet |
60 | 5.4 feet | 16.2 feet |
90 | 8.1 feet | 24.3 feet |
What is the difference between beam angle and field angle?
The beam angle measures a source’s intensity until it has fallen 50%. The field angle measures the angle of a source’s intensity until it has fallen 10%.
What does beam angle mean in downlights?
A beam angle is a measurement of how light is emitted or distributed from a source. A regular light bulb can have 360 degrees beam angle, unlike downlights that come in a range of different beam angles. The majority of LEDs and recessed downlights have a fairly narrow beam of 40 degrees.
What is beam spread angle?
Beam spread, or beam angle, measures the spread of light (the width of the beam) from a reflectorized light source. The beam spread number is important to know when deciding how much light you want displayed on an object, a sign, or on your floors.
What is the beam angle on a flood light?
Flood lights most often have a beam spread of more than 45 degrees and up to about 120 degrees; however, some lights that are marketed as floods may have a beam as narrow as 25 degrees.
What is the best beam angle for downlights?
60 degrees
The beam angle of 60 degrees is perfect for use in the living room. It is also known as floodlighting and suitable for standard ceiling heights. If you are looking to install only a few downlights in your room and still get your desired lighting, a downlight with 120 degrees beam angle is a great option.
How do I choose a downlight beam angle?
Downlight Beam Angle Most have a beam angle of 45° because they are recessed. By contrast, a regular light bulb would have a 360° beam angle. Because they are recessed, we recommend selecting downlights with a wider beam (of 60°) if you want soft diffuse lighting e.g. in the living room.
Is beam angle important?
Beam angles are measured in degrees, from the peak of the light’s intensity, to where the intensity drops off at around 50%. Generally speaking, a narrow beam angle will give you a concentrated light, which is ideal for accent lighting, and a wider beam angle will give you more general soft light.