# LightScope: Light & EV Meter — Lux, EV & Exposure Meter > Professional light measurement and analysis tool using device camera sensor. (iPhone/iPad app by Byungil Park.) - Source: https://appshunter.io/ios/app/lightscope-light-and-ev-meter/id1572227924 (this page in markdown: same URL + `.md`) - Developer: [Byungil Park](https://appshunter.io/developer/318781673) - Category: Graphics & Design, Productivity - Price: Free (on sale, was $2.99) - Age rating: 4+ - Requires: iOS 16.6 · 2 MB - Languages: American English, Korean, Japanese - Released: 2021-06-30 - Data updated: 2026-08-28 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/lightscope-light-and-ev-meter/id1572227924/reviews.md ## What is LightScope? LightScope is a comprehensive solution providing professional light measurement and analysis using your iOS device's camera sensor. 【Key Measurement Features】 • Illuminance (lux) Measurement: Calculates accurate illuminance by analyzing EXIF data from the camera sensor. Illuminance is derived using the formula: (F-number² / (Exposure Time × ISO)) × Calibration Factor. • Exposure (EV) Calculator: Converts measured illuminance to EV and suggests proper exposure combinations in standard stops for your ISO and aperture (or shutter) settings. • Luminous Intensity (candela) Calculation: Automatically calculates the luminous intensity of a light source based on the set distance. Uses the formula: Illuminance (lux) × Distance². • Color Temperature (K) & Tint Analysis: Precisely measures the light source's color temperature (1500K~15000K) and tint (green-magenta bias) by analyzing the camera's white balance sensor data — useful for identifying fluorescent and LED lighting. • Real-time Histogram: Visualizes the balance of shadows, midtones, and highlights through 16-level brightness distribution analysis. • Contrast Ratio Measurement: Evaluates the brightness ratio between bright and dark areas of a scene (based on 10th/90th percentiles) according to WCAG accessibility standards. • Noise Measurement (SNR): Calculates the signal-to-noise ratio in dB to evaluate image quality in the shooting environment. 【Advanced Features】 • Image Capture and Storage: Captures camera images at the time of measurement and stores them with measurement data. • Full-screen Image View: Zoom, pan, and rotate captured images for detailed inspection. • Gallery Saving: Save captured images to your device's photo library. • Measurement History and Trends: Save all measurements chronologically and chart trends for lux, EV, color temperature, contrast, and SNR. • Continuous Logging: Automatically record measurements at a set interval (1-60s) — great for lighting design and site surveys. • Full-Resolution Image Storage: Keep captured images at original quality for detailed inspection and gallery saving. • Export All History: Export every measurement as a CSV file or a PDF report. • Notes & Location Tags: Attach notes to measurements and optionally save the measurement location. • Home Screen Widget: See your last measurement (lux, color temperature, contrast, SNR) right on the home screen. • Camera Full-screen Mode: Hide panels to focus on the camera view while checking key measurements via a mini info panel. • Measurement Lock: Freeze exposure and white balance for stable, steady readings. • Spot Metering: In full-screen mode, tap anywhere to meter around that point. • Perfect Dark/Light Mode Support: All UI elements automatically adapt to the system theme. 【User Settings】 • Calibration Wizard: Enter a reading from a reference lux meter and the calibration factor is calculated automatically. Manual slider adjustment is also available. • Distance Setting: Set the distance to the light source for precise luminous intensity (cd) calculations. • Front/Rear Camera Selection: Choose the appropriate camera for your measurement situation. 【Technical Features】 • Support for measuring various light source types: natural light, LED, fluorescent, incandescent, etc. • Color temperature and tint sourced directly from the camera ISP's white balance estimation for reliable readings • 10-frame moving average filter for measurement stabilization • Center-weighted or spot (tap-to-meter) analysis for accurate evaluation of the main subject • Automatic exposure quality assessment based on histogram analysis Perfect tool for photographers, videographers, lighting designers, UI/UX developers, and anyone who needs accurate light measurements. ## Key features - Illuminance (lux) measurement - Luminous intensity (candela) calculation - Color temperature (K) analysis - Real-time histogram - Contrast ratio measurement - Image capture and storage - Measurement history and trends ## Recent user reviews (10 of 12) All indexed reviews: https://appshunter.io/ios/app/lightscope-light-and-ev-meter/id1572227924/reviews.md ### 5/5 — 영상 촬영에 좋은 앱 *2025-08-26* 정확한 색온도를 알아야 할 때 좋은 앱입니다. 우리나라 분이 개발하신 것 같아 구입했습니다. ### 5/5 — 2.0 좋아졌군요. *2025-05-13* 이전 버전보다 기능도 많아지고, 디자인도 많이 좋아졌군요. 잘쓸게요 ### 1/5 — 测量不准 *2024-02-25* 测试了十几款亮度测试软件；这个是收费且最不准确的，同一个光源，安卓和苹果的不同软件，其他测量都是300到600lux，这个测试只有50到60lux，建议避坑。 ### 1/5 — Medición incorrecta. *2023-01-25* Con ninguna de las dos cámaras hace una medición correcta de la luminosidad en un iPhone 12. Con el ajuste máximo de calibración (50) los valores son la mitad de lo que miden otras apps. En un entorno donde hay unos 250 luxes marca unos 130. No me sirve para nada. ### 1/5 — × *2022-06-11* あまりにもひどすぎる。絶対ダウンロードしない方がいい。 ### 1/5 — 使えない *2022-03-14* 仕事で照度計を持ち合わせていなかったため、試しに購入してみましたが、明らか低い値でしか表示されません。キャリブレーションの調整が可能ですが、他の方のレビュー通り、調整値が合っているのかよくわからない。 自動調整してより正確な値が出るバージョンアップを期待しております。 ### 4/5 — 가이드가 없어서 어려워요.. *2021-11-03* 측정중에 카메라 줌을 땡겨서 확대하니까 폰과 측정거리는 똑같은데 조도값이 엄청 상승하네요. ### 4/5 — 今後に期待！ *2021-09-30* ほかのレビューでもある通りほかの照度計とのズレがけっこうあり、キャリブレーションで調整とありますが調整があってるのか確かめるのにほかの照度計が必要になってしまいます。調整不要だと使えるのかなと。iPhoneで光が測れるのは画期的で素晴らしいと思います！進化版期待しています！ ### 1/5 — 全く使えない *2021-09-29* 測定器をもっているが大きく煩わしいためこちらのアプリを期待して購入してみたが期待した結果は得られなかった。 ※実機と比べてみたが大きく値が異なる 買わないことをおすすめします。 ### 1/5 — 使えない *2021-08-16* セールに釣られて購入しましたが、正確な値は出ません。 外カメラと内カメラの値も違いすぎて参考になりません。アプリの使用上内カメでないと使えないです…。 キャリブレーションで調整をするようにと書いてありましたが、キャリブレーションを最大にしても数値は実際のところまで上がりませんでした(JAPPY製照度計と比較) 光源までの距離を入れる欄もあり、何のためのアプリなのかわかりません。光源までの距離がわかる所ばかりで使うわけではないので。 **Developer response:** 率直な評価をありがとうございます。 それなりに頑張って作ったのに気に入らなかったんですね。 もう少し努力します。 ## Frequently asked questions about LightScope ### What is Light Scope used for? Light Scope is a professional tool that uses your device's camera sensor to measure and analyze various aspects of light, including illuminance, luminous intensity, and color temperature. It helps users understand and quantify light conditions for photography, videography, and design. ### How does Light Scope measure illuminance? Light Scope calculates illuminance in lux by analyzing EXIF data from your device's camera sensor. It uses a specific formula involving the F-number, exposure time, ISO, and a calibration factor for accuracy. ### Can Light Scope measure color temperature? Yes, Light Scope can precisely measure color temperature in Kelvin (K) within a range of 1500K to 15000K. It achieves this by converting RGB values to the XYZ color space using McCamy's formula. ### Does Light Scope support image capture? Yes, Light Scope allows you to capture images at the time of measurement and stores them along with the measurement data. These captured images can be viewed in full-screen, zoomed, panned, rotated, and saved to your device's photo library. ### How often is Light Scope updated? The latest version of Light Scope is 2.0, and it was last updated on May 13, 2025. This indicates a commitment to ongoing development and improvements. ### What devices is Light Scope available on? Light Scope is currently supported on iPhones. It is designed to leverage the camera sensor capabilities of these devices. ### What is the price of Light Scope? Light Scope is a paid application and costs $2.99. This one-time purchase grants you access to all its professional light measurement and analysis features. ### Does Light Scope have ads? No, Light Scope does not contain advertisements. As a paid application, it provides an uninterrupted user experience focused solely on its measurement and analysis functionalities. ## Version history (last 5 releases) ### 3.1 — 2026-08-26 A first-run guide now shows what LightScope can do before you start. • First-run guide — explains how the camera measures light • Pick a time range directly on the history chart; your choice is remembered • Clear message instead of an empty chart when a range has no readings • The Pro screen now leads with the feature you just reached for ### 3.0.1 — 2026-08-12 Improved the accuracy and reliability of measurement features. • Fixed the calibration wizard's 3-second measurement never completing • Improved spot metering — tap the screen and lux, exposure (EV) and candela are re-measured at that point • Measurement lock now freezes the preview as well as the readings, and saved photos match the locked moment • Fixed the Pro screen sometimes failing to load pricing, and added a retry button ### 3.0 — 2026-08-11 LightScope is now free! If you bought the app before, all Pro features unlock automatically. Massive 3.0 update: • Exposure (EV) calculator with shutter speed suggestions for your ISO and aperture • Improved color temperature engine + tint (green-magenta) display • Calibration wizard — auto-calibrate against a reference lux meter • Spot metering · Measurement lock (AE/AWB) • Continuous logging (1-60s interval) • Export all history as CSV/PDF • Full-resolution image capture • Notes & location tags • Home Screen widget ### 2.0 — 2025-05-13 LightScope is a comprehensive solution providing professional light measurement and analysis using your iOS device's camera sensor. 【Key Measurement Features】 • Illuminance (lux) Measurement: Calculates accurate illuminance by analyzing EXIF data from the camera sensor. Illuminance is derived using the formula: (F-number² / (Exposure Time × ISO)) × Calibration Factor. • Luminous Intensity (candela) Calculation: Automatically calculates the luminous intensity of a light source based on the set distance. Uses the formula: Illuminance (lux) × Distance². • Color Temperature (K) Analysis: Precisely measures color temperature in the range of 1500K~15000K by converting RGB values to XYZ color space using McCamy's formula. • Real-time Histogram: Visualizes the balance of shadows, midtones, and highlights through 16-level brightness distribution analysis. • Contrast Ratio Measurement: Evaluates the ratio between the brightest and darkest parts of a scene according to WCAG accessibility standards. • Noise Measurement (SNR): Calculates the signal-to-noise ratio in dB to evaluate image quality in the shooting environment. 【Advanced Features】 • Image Capture and Storage: Captures camera images at the time of measurement and stores them with measurement data. • Full-screen Image View: Zoom, pan, and rotate captured images for detailed inspection. • Gallery Saving: Save captured images to your device's photo library. • Measurement History and Trends: Save all measurements chronologically and visualize trends with graphs. • Camera Full-screen Mode: Hide panels to focus on the camera view while checking key measurements via a mini info panel. • Perfect Dark/Light Mode Support: All UI elements automatically adapt to the system theme. 【User Settings】 • Illuminance Calibration: Adjust the calibration factor for more accurate measurements based on your environment. • Distance Setting: Set the distance to the light source for precise luminous intensity (cd) calculations. • Front/Rear Camera Selection: Choose the appropriate camera for your measurement situation. 【Technical Features】 • Support for measuring various light source types: natural light, LED, fluorescent, incandescent, etc. • Algorithm optimization for stable color temperature calculation even in low-light environments • 10-frame moving average filter for measurement stabilization • Center-weighted image analysis for accurate evaluation of main subject quality • Automatic exposure quality assessment based on histogram analysis Perfect tool for photographers, videographers, lighting designers, UI/UX developers, and anyone who needs accurate light measurements. ### 1.4.0 — 2023-12-07 Added the ability to save a measurement list ## Apps similar to LightScope | App | Rating | Price | Category | | --- | --- | --- | --- | | [Designgraphik](https://appshunter.io/ios/app/designgraphik/id1529053747) | 4.7 (15) | $1.99 | Graphics & Design | | [Tapered Labels](https://appshunter.io/ios/app/tapered-labels/id1478188763) | 3.4 (5) | $0.99 | Graphics & Design | | [QRMaker - QRCode Generator](https://appshunter.io/ios/app/qrmaker-qrcode-generator/id6738868078) | — | Free | Graphics & Design | | [MoNo - convert to binary image](https://appshunter.io/ios/app/mono-convert-to-binary-image/id1575154535) | 4.8 (6) | $0.99 | Graphics & Design | | [Design AI - image generator](https://appshunter.io/ios/app/design-ai-image-generator/id6448249122) | — | $9.99 | Graphics & Design | | [Guernika](https://appshunter.io/ios/app/guernika/id1660407508) | 4.3 (8) | $1.99 | Graphics & Design | ## More apps by Byungil Park - [Crack Detector](https://appshunter.io/ios/app/crack-detector/id1530337221) - [Contacts Export to Sheet](https://appshunter.io/ios/app/contacts-export-to-sheet/id1532000113) - [내연봉계산기 - 실수령액, 연봉순위](https://appshunter.io/ios/app/id1564866857) - [Banzle - Video Player for Pets](https://appshunter.io/ios/app/banzle-video-player-for-pets/id1610958994) - [BikeCam Pro](https://appshunter.io/ios/app/bikecam-pro/id6473234309) All apps by Byungil Park: https://appshunter.io/developer/318781673 ## Related topics [screen brightness nits meter](https://appshunter.io/ios/topics/screen-brightness-nits-meter) · [luminosys](https://appshunter.io/ios/topics/luminosys) --- *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 2026-08-28.*