Coming Soon
Launching Soon · Free · Browser-Based

Your phone camera is about to become a professional light meter.

Spot-meter any scene, get instant ND filter and shutter-angle recommendations, compare lighting ratios, and preview false color exposure — no app to install, nothing uploaded. Luxmetry is in final testing now.

Launching Soon See What It Does
Works in any modern mobile browser · Camera access stays on your device
EV100
11.4
1,240 lux
Suggested ND
ND16
4.0 stops
Preview · live readout coming soon
Features

Five tools, one viewfinder

Everything a cinematographer or photographer needs to check exposure before rolling — built around how your phone's camera already sees the scene.

01 · ND FILTER CALCULATOR

Know your filter before you shoot

Meter the scene, enter your ISO, aperture, frame rate, and shutter angle, and get the nearest standard ND filter recommendation in seconds.

02 · SHUTTER ANGLE / PANNING

Built for the 180° rule

Set your target shutter angle for natural motion blur on pans, and Luxmetry works out the exact shutter speed and ND stop needed to hit it.

03 · FALSE COLOR

See exposure, not guesswork

A live cine-style false color overlay flags crushed blacks, clipped highlights, and skin-tone reference zones directly on your camera feed.

04 · LIGHTING RATIOS

Compare key, fill, and background

Tap up to four points in frame and Luxmetry calculates the stop difference and ratio between them — key-to-fill, key-to-background, and more.

05 · REFERENCE CALIBRATION

Real EV and lux, not just relative

Upload one photo shot with known ISO, aperture, and shutter, and Luxmetry calibrates itself to output accurate EV100 and lux from then on.

06 · ON-DEVICE ONLY

Nothing leaves your phone

Metering, false color, and calibration all run locally in your browser using the camera and canvas APIs — no account, no upload, no tracking.

How It Works

From open tab to ND recommendation in four taps

Open Luxmetry and allow camera access

Works in Safari on iOS and Chrome on Android — no install, no app store.

Tap the scene you want to expose for

Luxmetry spot-meters that point and shows an EV and lux readout instantly.

Enter your camera settings

ISO, aperture, frame rate, and shutter angle — Luxmetry compares your target shutter speed to what the light actually needs.

Get your ND filter and go

Switch to false color or ratio mode to double-check exposure and lighting balance before you roll.

FAQ

Common questions

Can my phone camera really work as a light meter?

Yes. Luxmetry reads brightness directly from your phone's camera feed and converts it into an exposure value. Because browsers don't expose a phone's real ISO, shutter, and aperture data, readings start out relative — you can calibrate them into accurate EV and lux values by uploading one reference photo shot with known settings.

How does the ND filter calculator work?

Enter your ISO, aperture, frame rate, and target shutter angle. Luxmetry meters the scene, works out the shutter speed needed for a correct exposure, compares it to the shutter speed your shutter angle requires, and recommends the closest standard ND filter to close the gap.

What is shutter angle and why does it matter for ND filters?

Shutter angle is the cinema equivalent of shutter speed, expressed relative to frame rate — a 180-degree angle gives the natural motion blur audiences expect. Because it ties shutter speed to frame rate rather than to the light in the scene, an ND filter is usually the only way to keep both correct exposure and a 180-degree angle in bright conditions.

Is Luxmetry free to use?

Yes, the meter, ND calculator, false color tool, ratio comparison, and calibration are all free and run entirely in your browser.

Does Luxmetry upload my camera feed or photos anywhere?

No. All metering and calibration happens on-device using your browser's camera and canvas APIs. Nothing is uploaded to a server.

Luxmetry is launching soon.

No sign-up, no download — just open it on your phone and tap to meter. Check back shortly.

Launching Soon