How do I measure the lumens of a flashlight?

[mustang51]

How can I measure how many lumens my flashlight has? is there some kind of meter capable of measuring lumens?

 

[aryntha]

"Lumens", no. Not with a simple meter. It requires a spherical integration meter. These are...rather expensive, and not common.

Labsphere : Light Measurement Spheres

Complete systems for this, or handheld units, you're talking $3000 and up.

Candlepower/candela/foot-candles on the other hand is easier, but not really nearly as telling or comparable across different lights.

 

[mustang51]

So how do I know if the flash light I built is really 1000 lumens and not less?

 

[Blord]

If you know the LED and the current you can compare to this list.

Quick reference list of common powerleds brightness bins at Tj=25C
Actual brightness will be around 10% less due to heating of the led.


Cree XR-E, XP-E & XP-G brightness at 350mA

P4 80.6-87.4 lm @ 350mA
Q2 87.4-93.9 lm @ 350mA
Q3 93.9-100 lm @ 350mA
Q4 100-107 lm @ 350mA
Q5 107-114 lm @ 350mA
R2 114-122 lm @ 350mA
R3 122-130 lm @ 350mA
R4 130-139 lm @ 350mA
R5 139-148 lm @ 350mA
S2 148-156 lm @ 350mA
S3 156-164 lm @ 350mA
S4 164-172 lm @ 350mA


Cree XR-E and XP-E brightness at 1A

P4 177-192 lm @ 1A
Q2 192-207 lm @ 1A
Q3 207-220 lm @ 1A
Q4 220-233 lm @ 1A
Q5 233-251 lm @ 1A
R2 251-268 lm @ 1A
R3 268-286 lm @ 1A*
R4 286-306 lm @ 1A


Cree XP-G brightness at 1A

R2 285-305 lm @ 1A
R3 305-325 lm @ 1A
R4 325-348 lm @ 1A
R5 348-370 lm @ 1A
S2 370-390 lm @ 1A
S3 390-410 lm @ 1A*
S4 410-430 lm @ 1A


Cree XP-G brightness at 1.5A

R2 380-406 lm @ 1.5A
R3 406-433 lm @ 1.5A
R4 433-463 lm @ 1.5A
R5 463-493 lm @ 1.5A
S2 493-520 lm @ 1.5A
S3 520-547 lm @ 1.5A*
S4 547-573 lm @ 1.5A

Cree XM-L brightness at 700mA

T5 260-280 lm @ 700mA
T6 280-300 lm @ 700mA*
U2 300-320 lm @ 700mA
U3 320-340 lm @ 700mA


Cree XM-L brightness at 1.5A

T5 504-543 lm @ 1.5A
T6 543-582 lm @ 1.5A*
U2 582-621 lm @ 1.5A
U3 621-660 lm @ 1.5A


Cree XM-L brightness at 3.oA

T5 845-910 lm @ 3.0A
T6 910-975 lm @ 3.0A*
U2 975-1040 lm @ 3.0A
U3 1040-1105 lm @ 3.0A


Cree MC-E brightness at 350mA per die, 1.4A total current

H 280-320 lm @ 350mA (1.4A)
J 320-370 lm @ 350mA (1.4A)
K 370-430 lm @ 350mA (1.4A)
M 430-490 lm @ 350mA (1.4A)
N 490-550 lm @ 350mA (1.4A)*
P 550-620 lm @ 350mA (1.4A)


MC-E brightness at 700mA per die, 2.8A total current

H 490-560 lm @ 700mA (2.8A)
J 560-648 lm @ 700mA (2.8A)
K 648-753 lm @ 700mA (2.8A)
M 753-858 lm @ 700mA (2.8A)
N 858-962 lm @ 700mA (2.8A)*
P 962-1085 lm @ 700mA (2.8A)


Luminus SST-50 brightness at 1.75A, 350mA per mm²

F 275-350 lm @ 1.75A (350mA/mm²)
G 350-425 lm @ 1.75A (350mA/mm²)
H 425-500 lm @ 1.75A (350mA/mm²)
J 500-600 lm @ 1.75A (350mA/mm²)*
K 600-700 lm @ 1.75A (350mA/mm²)


Luminus SST-50 brightness at 2.8A, 560mA per mm²

F 454-576 lm @ 2.8A (560mA/mm²)
G 576-701 lm @ 2.8A (560mA/mm²)
H 701-825 lm @ 2.8A (560mA/mm²)
J 825-990 lm @ 2.8A (560mA/mm²)*
K 990-1155 lm @ 2.8A (560mA/mm²)


Luminus SST-50 brightness at 5A, 1A per mm²

F 743-945 lm @ 5A (1A/mm²)
G 945-1148 lm @ 5A (1A/mm²)
H 1148-1350 lm @ 5A (1A/mm²)
J 1350-1620 lm @ 5A (1A/mm²)*
K 1620-1890 lm @ 5A (1A/mm²)


Luminus SST-90 brightness at 3.15A, 350mA per mm²

K 600-700 lm @ 3.15A (350mA/mm²)
L 700-850 lm @ 3.15A (350mA/mm²)
M 850-1000 lm @ 3.15A (350mA/mm²)
N 1000-1200 lm @ 3.15A (350mA/mm²)*
P 1200-1450 lm @ 3.15A (350mA/mm²)


Luminus SST-90 brightness at 5A, 560mA per mm²

K 930-1085 lm @ 5A (560mA/mm²)
L 1085-1318 lm @ 5A (560mA/mm²)
M 1318-1550 lm @ 5A (560mA/mm²)
N 1550-1860 lm @ 5A (560mA/mm²)*
P 1860-2248 lm @ 5A (560mA/mm²)


Luminus SST-90 brightness at 9A, 1A per mm²

K 1620-1890 lm @ 9A (1A/mm²)
L 1890-2295 lm @ 9A (1A/mm²)
M 2295-2700 lm @ 9A (1A/mm²)
N 2700-3240 lm @ 9A (1A/mm²)*
P 3240-3915 lm @ 9A (1A/mm²)


Seoul SemiConductor P4 brightness at 350mA

S1 54-60 lm @ 350mA
S2 60-70 lm @ 350mA
T1 70-80 lm @ 350mA
T2 80-91 lm @ 350mA
U1 91-100 lm @ 350mA
U2 100-109 lm @ 350mA*
U3 109-119 lm @ 350mA


Seoul SemiConductor P4 brightness at 1A

S1 127-141 lm @ 1A
S2 141-165 lm @ 1A
T1 165-188 lm @ 1A
T2 188-214 lm @ 1A
U1 214-235 lm @ 1A
U2 235-256 lm @ 1A*
U3 256-280 lm @ 1A


Seoul SemiConductor P7 brightness at 1.4A total current, 350mA per die

A 251-326 lm @ 1.4A (350mA)
B 326-400 lm @ 1.4A (350mA)
C 400-457 lm @ 1.4A (350mA)
D 457-514 lm @ 1.4A (350mA)*
E 514-629 lm @ 1.4A (350mA)


Seoul SemiConductor P7 brightness at 2.8A total current, 700mA per die

A 440-570 lm @ 2.8A (700mA)
B 570-700 lm @ 2.8A (700mA)
C 700-800 lm @ 2.8A (700mA)
D 800-900 lm @ 2.8A (700mA)*
E 900-1100 lm @ 2.8A (700mA)


Lumileds Luxeon Rebel brightness at 350mA

040 40+ lm @ 350mA
050 50+ lm @ 350mA
060 60+ lm @ 350mA
070 70+ lm @ 350mA
080 80+ lm @ 350mA
090 90+ lm @ 350mA
100 100+ lm @ 350mA*
110 110+ lm @ 350mA


Lumileds Luxeon Rebel brightness at 1A

040 84+ lm @ 1A
050 105+ lm @ 1A
060 126+ lm @ 1A
070 147+ lm @ 1A
080 168+ lm @ 1A
090 189+ lm @ 1A
100 210+ lm @ 1A*
110 231+ lm @ 1A


*(maximum available flux bin as of writing)

Sources:
CREE | Lighting LEDs Documentation
http://www.luminus.com/content1454
Seoul Semiconductor, Inc
LUXEON Rebel White LEDs | Philips Lumileds Lighting Company

 

[HaloBlu]

Don't know how well they compare but people do build DIY integrating spheres. You need a good coating. Improving the DIY integrating sphere

 

[mustang51]

My LED is a XM-L-H it suppose to be a 1000 lumen LED @ 3000mA.