Real-Time Camera Light Meter
Scan surface illumination using your device's optical sensor or simulate standard lighting environments. Calculates surface Lux and Foot-Candles via CIE photopic weighting with real-time stability tracking.
Illumination Stability Stream
Stable (±2%)Natural, relaxing illumination meeting IESNA standards for living rooms, bedrooms, and dining spaces.
IESNA Illuminance BenchmarksFull Guide →
- Bedroom (Sleeping):100 lx
- Living Room (Ambient):150 lx
- Kitchen (Prep Counters):500 lx
- Home Office (Desk Study):450 lx
- Fine Craft / Workshop:750 lx
How Camera Sensors Measure Lux vs. Dedicated Light Meters
Understanding optical luminance weighting and sensor calibration limits.
CIE Photopic Curve
Human eyes are most sensitive to green light (555 nm). Our algorithm applies standard ITU-R BT.709 photometric coefficients (0.2126 Red + 0.7152 Green + 0.0722 Blue) to convert RGB sensor values into perceived luminance.
Automatic Gain & Exposure
Smartphones continually adjust exposure and ISO. Use the Tare Zero and Calibrate controls against known bulb values to compensate for hardware auto-exposure shifts.
Luminance vs Illuminance
A camera measures luminance (light reflected into the lens), whereas a professional lux meter measures illuminance (light falling on a flat diffuser). Pointing the camera at a matte white sheet yields the most accurate Lux approximation.
Camera Lux Meter FAQs
How accurate is a webcam or smartphone camera as a lux meter?
Smartphone cameras provide good relative readings (identifying whether a room is 100 Lux vs. 500 Lux), with approximately ±15% to 25% precision compared to a laboratory photometer. Use our calibration slider to match a reference source for enhanced accuracy.
Is my camera video stream private and secure?
Yes, 100% private. All frame extraction and pixel luminance calculations occur strictly inside your device's browser memory using client-side JavaScript. No video, images, or telemetry are ever recorded or transmitted over the internet.