LumenLab - Lux Meter

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