Circadian Optics · $$$ · Updated August 24, 2026
Langham
A top-10 lamp for melanopic output, #7 of 57. No flicker at any setting.
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Is it strong enough?#7 of 57
Yes. 1.4× the 10,000 lux benchmark.
13,590 m-EDI at 1 ft
Is it comfortable to sit in front of?Standard
Mostly. Moderate glare.
162 at 1 ft · median 112
Does it flicker?No risk
No, at full power or dimmed.
0.1% modulation at max · 0.3% dimmed
Flicker index
0.0002
SVM
0.003
What does the light look like?5700K
Cool daylight, excellent color.
CRI Re 95 · R9 94
2700K warm7500K cool
All test data
Light outputMeasured at 1 ft and 2 ft
m-EDI
13,590
n/a at 2 ft
Lux
14,090
n/a at 2 ft
CLa
26,355
n/a at 2 ft
Glare
162
n/a at 2 ft
m-EDI 13,590 at 1 ft
Median 3,43010,000 benchmark1 ft
Glare 162 at 1 ft
Median 1121 ft
SpectrumOutput at the highest setting
Melanopic DER
0.96
m-EDI per lux. Daylight (D65) is 1.0.
CCT
5700K
Fixed
Gap from natural light
8%
Very close. Average spectral difference (ASD) from daylight at the same color temperature, 425 to 690 nm.
Lamp outputBody-clock zone (melanopic, CIE S 026)Natural light, same color temperature
FlickerGreen is safe, amber is acceptable, red is past the limit
Full powerDimmed (Halfway (50%))
Percent flicker
0.1% · 0.3%
Flicker index
0.0002 · 0.0007
SVM
0.003 · 0.005
PstLM
0.081 · 0.016
Assist Mp
0.007 · 0.007
Waveform, 1 second
A flat line near 1.0 means steady light.
Color renderingHow accurately colors and skin tones look under this lamp
CRI Re
95
R9 (deep red)
94
TM-30 Rf
94
TM-30 Rg
99
Neutral saturation
Specifications
- Form factor
- Desktop
- Brightness
- Continuous
- Color temperature
- Fixed
- Power
- 66 W
- Voltage
- 100-240V
- Cord length
- 9.3 ft
- Mounting
- None
- Extra features
- Works with a smart plug
- Available in
- United States, Canada
