LightScope: Light & EV Meter

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.