LumenLab vs Light Meter LuMe

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

LuMe is a pro-grade light meter and exposure calculator built for film photographers. Whether you're shooting medium format on a Mamiya, large format on a 4×5, or 35mm on a Leica, LuMe gives you the exposure intelligence your film camera doesn't have. METERING MODES FOR EVERY SITUATION • Matrix — averages the whole scene for balanced exposures • Center-weighted — emphasizes the middle, like a classic SLR meter • Spot — measures a small area you tap, just like a 1° spot meter • Zone System — Ansel Adams' tonal mapping (Zones I–IX) right in your viewfinder MULTI-POINT SPOT METERING Place up to four spot markers anywhere on your scene. Read each EV at a glance, evaluate contrast range, and place tones with intention. LIDAR SPOT DISTANCE (on Pro devices) See the physical distance to any metered spot — useful for hyperfocal setup and verifying focus on rangefinders and manual-focus lenses. RECIPROCITY CORRECTION FOR EVERY FILM STOCK Long exposures don't behave linearly on film. LuMe applies the Schwarzschild exponent for your stock — Tri-X, TMax, Portra, Ektar, Velvia, and more — so you don't need printed tables in your bag. DEPTH OF FIELD CALCULATOR Hyperfocal distance, near limit, far limit — for 35mm, APS-C, medium format (6×4.5, 6×6, 6×7), and large format (4×5). One tap. FLASH GUIDE NUMBER CALCULATOR GN, distance, power fraction → f-stop. Solved. LIVE EXPOSURE TOOLS • Histogram overlay • Highlight/shadow clipping warnings • ND filter compensation • Aperture priority & shutter priority • Exposure compensation dial • ISO and shutter range constraints (cap at your film speed) BUILT FOR THE WAY FILM PHOTOGRAPHERS ACTUALLY SHOOT • Spot meter a high-contrast scene; place highlights on Zone VII • Apply reciprocity for a 30-second exposure on Tri-X • Calculate hyperfocal for landscape work on Portra 400 • Verify a flash setup before burning a frame LuMe replaces your handheld meter, reciprocity card, DoF chart, and flash calculator with one tool that fits in your camera bag. Available in 16 languages: English, German, French, Spanish, Italian, Portuguese, Dutch, Swedish, Polish, Turkish, Russian, Arabic, Japanese, Korean, Chinese (Simplified & Traditional). LUME PRO • $6.99 USD for lifetime access Privacy policy: https://lume.contraststudio.app/privacy.html Terms of Use: https://lume.contraststudio.app/terms.html