LumenLab - Lux Meter
Camera Light Meter · EV
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Estimate lux from iPhone camera exposure data. EV, stats, calibration, and CSV export.
LumenLab is 100% software, using your iPhone's built-in camera — no external hardware required. LumenLab turns your iPhone's rear camera into a real-time light meter. By reading the camera's exposure metrics (ISO, shutter, aperture), it computes the illuminance of your environment in lux — perfect for photographers, plant growers, interior designers, and anyone who cares about lighting.
KEY FEATURES
• Real-time lux reading using camera exposure parameters
• Color-coded zones: dark · dim · normal · bright · glaring
• Lighting recommendations for each level
• One-tap session reset
• Core measurement works offline — no tracking, no ads, no account
USE CASES
• Photographers checking ambient light levels
• Cinematographers metering scene illumination
• Plant growers ensuring grow-light intensity
• Interior designers checking room brightness
• Office ergonomics (recommended 300–500 lux)
• Reading nook brightness check
PRO FEATURES (optional subscription)
• Advanced metrics row: EV, ISO, Shutter, Aperture (f/)
• Session statistics: minimum, average, maximum lux
• Calibration multiplier to align with a professional reference meter
• CSV export of full session log (timestamp, lux, EV, calibration factor)
• Zero ads forever
HOW IT WORKS
LumenLab opens the camera (no recording, no preview saved), reads the device's auto-exposure metrics every frame, and applies the photographic equation:
EV = log₂(N²/t) − log₂(S/100)
lux ≈ 2.5 × 2^EV × calibration
This is a practical camera-exposure estimate. For critical comparisons, calibrate against a known light source or reference meter.
LIMITATIONS
The iPhone camera is not a calibrated photometer. Readings are estimates and can vary by device, lens, scene reflectance, and auto-exposure behavior. Not suitable for regulatory, lab, or safety measurements.
PRIVACY
The camera is opened only to read auto-exposure metadata. No images, video, or audio are recorded, saved, or transmitted. No analytics, no ads, no account. StoreKit is used only for the optional Pro subscription.
SUBSCRIPTION INFO
• Payment will be charged to your Apple ID account at confirmation of purchase.
• Subscription automatically renews unless auto-renew is turned off at least 24 hours before the end of the current period.
• Your account will be charged for renewal within 24 hours prior to the end of the current period.
• You can manage and cancel your subscriptions by going to App Store → Account → Subscriptions.
Privacy Policy: https://frexx.top/lumenlab/privacy.html
Terms of Use: https://frexx.top/lumenlab/terms.html
SUPPORT
jie.xiang.jm@gmail.com
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
LumenLab now adds Room Fit guidance, turning the lux reading into clearer advice for reading, desk work, detail tasks, bright spaces, and glare risk. The top controls also have larger tap targets, and the simulator camera fallback, Pro export, and calibration flow were rechecked for this release.
The developer, 杰 向, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 杰 向
- Size
- 671.7 KB
- Category
- Photo & Video
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English and Simplified Chinese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- LumenLab Pro Weekly $2.99
- LumenLab Pro Yearly $19.90
- Copyright
- © 2026 Clawbot