# Lux Light Meter · Photometer — Lux · EV · Modes · History > iPhone illuminance and exposure meter with history and photography features. (iPhone/iPad app by Kyu-Hee Jang.) - Source: https://appshunter.io/ios/app/lux-light-meter-photometer/id6759858193 (this page in markdown: same URL + `.md`) - Developer: [Kyu-Hee Jang](https://appshunter.io/developer/1587578867) - Category: Utilities, Productivity - Price: Free - Rating: 4.80/5 from 4 App Store ratings - Age rating: 17+ - Requires: iOS 16.4 · 56 MB - Languages: American English - Released: 2026-03-03 - Data updated: 2026-08-22 - Monetization: ad-supported - User reviews in markdown: https://appshunter.io/ios/app/lux-light-meter-photometer/id6759858193/reviews.md ## What is Lux Light Meter · Photometer? Measure light properly — in lux, foot-candles, EV, or PPFD for plants — using your iPhone's camera to read the light falling on the scene. GROW LIGHTS & PLANTS • PPFD estimated from your live reading, matched to your light source: white LED, HPS, fluorescent or daylight • DLI for a 12, 14, 16 or 18 hour photoperiod, so you can tell whether a shelf actually reaches a seedling's daily light target • These are spectrum-based estimates, not a calibrated PAR sensor. Read them as guidance for placing lights, not as lab data. FOUR MEASURING MODES • Auto — radial gauge with the closest real-world reference shown live • Outdoor — a log scale to 100,000 lx, from deep twilight through overcast and direct sun • Indoor — 10 to 10,000 lx, from corridor and living room up to reading desk, drafting and surgical levels • Photo — EV at ISO 100 with a suggested shutter speed HISTORY THAT ADDS UP • Every reading saves automatically, with a 7-day trend chart and plain-language insight such as "+12% vs your 7-day average" • Notes and favourites — label a reading "kitchen window 3pm" and star it • Compare any two saved readings side by side • Export everything as CSV, or share a single reading as an image MEASUREMENT DETAIL • Kalman-smoothed readings, so there is no jitter to read through • Min, max and average with elapsed time • Log-scale range bar in Outdoor and Indoor modes • Lux, foot-candle and EV units • Calibration factor — scale every reading by a multiplier to match a reference meter you trust WHO USES IT Indoor gardeners and grow-tent owners · photographers and filmmakers · electricians and lighting installers · studio engineers · workplace and office ergonomics checks · industrial lighting surveys HOW IT WORKS Readings are estimated from the back camera's exposure, so this is a reflected-light measurement: point the back of the phone at the surface you care about and keep the lens clean and unshaded. Because it reads reflected light, a white wall and a dark carpet under identical lighting will not read the same, and very dim scenes are the least reliable. Cameras differ between models, so for absolute numbers set the calibration factor against a meter you trust. Available in 25 languages. ## Key features - Precise ambient light measurement (lux) - Multiple measurement modes (Auto, Outdoor, Indoor, Photo) - Measurement history with trend charts - Add notes and favorites to readings - Compare saved readings side-by-side - CSV export for data analysis - EV exposure value for photographers ## Frequently asked questions about Lux Light Meter · Photometer ### What is Lux Light Meter used for? Lux Light Meter turns your iPhone into a precise illuminance meter. It measures ambient light in lux and provides exposure values for photographers, with features like measurement history and CSV export. ### Does Lux Light Meter have ads? Yes, Lux Light Meter contains advertisements. As a free utility app, it utilizes ads to support its development and ongoing service. ### What devices does Lux Light Meter support? Lux Light Meter is available for iPhone and iPod touch devices. It is designed to leverage the sensors present on these Apple mobile devices. ### How accurate is Lux Light Meter? The app aims for precise ambient light measurement using Kalman-smoothed sensor readings. It also offers a calibration offset feature for fine-tuning sensor accuracy in ±1 lx steps. ### Can I save and review my light measurements with Lux Light Meter? Yes, Lux Light Meter automatically saves every reading and provides a 7-day trend chart. You can add notes, mark favorites, and compare saved readings side-by-side. ### Is Lux Light Meter suitable for professional photography? Yes, Lux Light Meter includes a 'Photo' mode that provides EV @ ISO 100 readout and suggested shutter speed at f/2.8, making it a useful tool for photographers. ### How often is Lux Light Meter updated? The latest version of Lux Light Meter is 1.0.16, and it was last updated on June 22, 2026. This indicates a recent update, suggesting active development and maintenance. ### What languages does Lux Light Meter support? Lux Light Meter is available in 14 different languages, making it accessible to a global user base. This broad language support enhances its usability for international users. ## Version history (last 5 releases) ### 1.0.29 — 2026-08-19 New Room Survey: measure several spots in one pass and get the average, a per-spot verdict against your chosen lighting standard, and the uniformity score used in lighting practice. The opening screen also no longer stalls when the network is slow. Thanks for the reviews and feedback! ### 1.0.27 — 2026-08-06 Ads no longer interrupt you mid-task. Anything full-screen now waits until you have finished what you were doing, and the app stops showing a blank pause where an ad failed to load. ### 1.0.26 — 2026-08-05 Starting a measurement is no longer interrupted — the app gets straight to work, and anything that needs your attention waits until you are done. ### 1.0.25 — 2026-08-03 We fixed a rare crash some users saw on launch, along with performance and stability improvements. Thank you for your patience and for helping us make the app better! ### 1.0.24 — 2026-08-01 We fixed a rare crash some users saw on launch, along with performance and stability improvements. Thank you for your patience and for helping us make the app better! ## More apps by Kyu-Hee Jang - [Calculator+ Tip Tax BMI Unit](https://appshunter.io/ios/app/calculator-plus-tip-tax-bmi-unit/id1587591476) - [QR Lens+ Barcode Scanner Pro](https://appshunter.io/ios/app/qr-lens-plus-barcode-scanner-pro/id1590631012) - [Sound Noise Meter+ dB SPL](https://appshunter.io/ios/app/sound-noise-meter-plus-db-spl/id1593197145) - [Tremor Vibration Meter](https://appshunter.io/ios/app/tremor-vibration-meter/id6759666731) - [Barometer: Air Pressure](https://appshunter.io/ios/app/barometer-air-pressure/id6759883097) All apps by Kyu-Hee Jang: https://appshunter.io/developer/1587578867 ## Related topics [boston scientific lux](https://appshunter.io/ios/topics/boston-scientific-lux) · [lux light meter](https://appshunter.io/ios/topics/lux-light-meter) · [lux meter light](https://appshunter.io/ios/topics/lux-meter-light) · [lumens meter](https://appshunter.io/ios/topics/lumens-meter) · [luminos meter](https://appshunter.io/ios/topics/luminos-meter) · [foot candle light meter](https://appshunter.io/ios/topics/foot-candle-light-meter) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-22.*