What Candela does

Candela reads the ambient light sensor already built into most Android phones and shows the result as a live number, in lux, foot-candles, or EV at ISO 100. A ring display spans six decades of light, from moonlight to direct sun. Five named zones (Dark, Dim, Comfortable, Bright, Harsh) tell you in plain words what the current level means, instead of leaving you to interpret a raw number.

For photographers, Candela adds a full exposure suggestion for the current light: an ISO, an aperture, and the nearest standard shutter speed. For everyday use, it keeps a 60-second trend of the reading plus the session's minimum, average, and maximum. A reference chip compares the live number against 16 familiar situations, such as a reading lamp or an overcast sky.

Screenshots

Candela reading 369 lux on a gauge, with a bar chart of recent readings. — Light meter, honestly

Candela showing a reading of 185 fc in the Bright zone, compared to an overcast day. — Light for your plants

Candela showing an exposure value of 12.0 EV with a harsh-light warning. — For photographers

A low reading of 7 lux in the dark zone. — Too dark to read?

A scrollable reference list of everyday light levels, from a moonless night at 0.001 lux to a hallway at 100 lux. — 16 everyday situations

Settings showing the film speed and aperture used for EV, a calibration offset slider at 0%, and the app version. — Your units, your offset

Features

Live lux readingWatch the light level update in real time, with a choice of fast or slow response and a peak-hold value for the highest reading in a session.
Three unitsSwitch between lux, foot-candles, and photographic EV at ISO 100, depending on what you are measuring for.
Exposure triangle for photographersPoint the phone at your light source and Candela shows an ISO, aperture, and the nearest standard shutter speed for that light level.
Five task zonesThe app sorts each reading into Dark, Dim, Comfortable, Bright, or Harsh, so a lux number turns into a plain answer.
Session trendA 60-second rolling chart, plus the session's minimum, average, and maximum, shows how the light has changed while you watch.
Everyday comparisonsA reference chip matches your reading against 16 common light levels, from moonlight to direct sunlight, so the number has context.
Manual calibrationAdjust the reading by up to 30 percent in either direction to line it up against a reference meter you trust.
Dark mode and two languagesCandela works in a dark or light theme, in tablet and landscape layouts, and in English or Urdu.

How it works

Candela reads the phone's ambient light sensor and converts the raw value into lux. It then calculates foot-candles and EV from that same number and places it into one of the five task zones.

Most phone light sensors are not calibrated instruments, and many are capped by the manufacturer, often somewhere between 30,000 and 65,000 lux. Candela says this plainly in the app and flags a reading that may have hit that cap, rather than presenting the number as exact.

What it can't do

Phone sensors aren't calibrated instruments, so readings are for comparison and rough estimates, not certified measurements.
The app needs a phone with an ambient light sensor; Google Play will hide the listing from phones that don't have one.
It measures illuminance in lux or foot-candles, not lumens, color temperature, or PAR/PPFD for grow lights.
The reading comes from the sensor at the top of the phone, not through the camera lens, so it reflects the light at that spot, not a framed photo.

Privacy

Candela doesn't ask you to sign up or log in, and it doesn't collect your name, email, contacts, photos, location, camera, or microphone. Settings such as units and calibration stay on the phone.

This version of the app has no internet access at all, so it has no way to send anything anywhere. There are no ads in this version; a future update could change that.

Read the full Candela privacy policy

Questions

Is Candela available on Google Play yet?

Not yet. It's in closed testing while Google reviews it for production release.

Does Candela work without internet?

Yes. This version has no internet access at all, so everything runs on your phone.

Why doesn't it ask for any permissions?

The light sensor doesn't need one, and the app has no camera, microphone, location, or network feature to ask permission for.

What happens on a phone with no light sensor?

Candela detects this and shows a plain message instead of displaying a fake reading.

How accurate is the reading?

It's screening-grade: good for comparing light levels and rough exposure estimates, not a substitute for a calibrated light meter.

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Candela