stop.

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The light meter that lives in your pocket.

No install No subscription Works offline Negative film calibrated
The state of play

Existing meters all fail the same way.

If you shoot film, you already know this. The tools for reading light are either overbuilt and overpriced, locked to one platform, or asking you to pay rent for something a thumbwheel should do for free.

01 / Price

Dedicated meters start at three hundred quid.

A Sekonic in your bag is beautiful. It is also a month of film. Most shooters never owned one, never will, and work around it with guesswork or Sunny 16.

02 / Platform

The good apps are all iOS-only.

Pixel shooter? Older Android? Borrowed phone on a shoot? You are out of luck or you are using something that looks like a 2011 calculator.

03 / Principle

Nobody should pay a subscription for a spot meter.

A light meter is a ruler. You do not rent a ruler. If the app nags you for £4.99 a month just to let you use a third metering mode, the app is not the problem, the pricing model is.

How it works

Three taps between the scene and the shutter.

No account. No install prompt. No onboarding carousel. Open the link, point the phone, read the number.

01 Open

Open the app.

Tap the link. The viewfinder is live in under a second. It works in Safari, Chrome, and anything else with a camera. There is nothing to install and no account to sign up for.

02 Point

Point at your scene.

The camera reads the light thirty times a second. Centre-weighted by default. Tap anywhere on the frame to spot-meter that exact patch. Hold to lock the reading while you compose.

03 Dial

Dial your shot.

Lock aperture, shutter, or ISO. The other two update in real time. Drop in a film preset for Portra, HP5, or whatever is loaded, and the meter adjusts for it.

Watch it in action

Four scenes. Four stops of light. One pocket.

Sunny park, overcast street, cafe window, dusk. The meter reads each scene and dials in aperture, shutter, ISO, and the film stock you are actually shooting.

Sunny 16 calibration

Calibrated once. Trusted forever.

Every phone's light sensor is slightly off. Point stop. at a known scene once — Sunny 16 handles the rest — and every reading from now on is correct to within a third of a stop.

Portra 160 HP5 Plus Portra 400 CineStill 800T Tri-X Ektar 100 Delta 3200 Velvia 50
What it does

Only the tools that belong on a meter.

Nothing fluffy. No social feed, no photo editor, no gamification. The four things you actually use on a shoot, done properly.

01

Live metering

Thirty readings a second straight from the camera sensor. Centre-weighted by default, average or spot on demand.

02

Film stock presets

Portra, Ektar, Gold, HP5, Tri-X, T-Max, CineStill and more. Tap a stock, the ISO and reciprocity curve follow.

03

EV compensation

Plus or minus three stops in third-stop clicks. Useful for backlit subjects, snow, stage light, anything the average cannot see for you.

04

Spot metering

Tap anywhere in the frame to meter that exact patch. Hold to lock. Works like the 1-degree spot on a Sekonic, minus the three hundred quid.

Calibration

"Calibrated against Sunny 16. Within a third of a stop after a thirty-second setup."

Every phone sensor is slightly different. The first time you open Stop it walks you through a quick calibration against a grey card or a blue-sky reading. Thirty seconds. After that, the readings match a dedicated meter closely enough that you will stop second-guessing it.

Being straight with you Negative film is forgiving, so Stop works beautifully for it. Slide film, where a third of a stop actually matters, wants a native app with direct sensor access. That is on the roadmap. Until it ships, a browser meter is not the tool for Velvia.
Who this is for

Built for people who already know what a stop is.

Three people, three reasons. If one of these sounds like you, you will understand the app in about forty seconds.

-2 EV The film shooter

You shoot a Pentax, a Mamiya, or anything older than you are.

Your meter died in 1997 or was never installed. Right now you Sunny 16 it and cross your fingers. Stop gives you a proper reading in the three seconds you have before the light moves.

Portra 400HP5 PlusEktar 100
•0 EV The cinematographer

You pull shutter angles on a Bolex or a Super 8 and want a sanity check.

Stop reads in EV and converts to shutter angle and T-stop if you want it to. It is the backup meter that lives in the pocket of the jacket you already own.

CineStill 800TVision3 500TTri-X Reversal
+2 EV The student

You are learning exposure on a course and the theory only clicks when you can see it move.

Lock aperture, watch shutter follow. Lock shutter, watch aperture follow. The exposure triangle stops being an abstract diagram about ten minutes in.

Tri-X 400T-Max 400Kentmere 100
Pricing

Pay once. Or not at all.

The web version is free forever. Full feature set, no nag screens, no data collection. If you want the native app when it lands, it is three quid, one time.

Web app / PWA
Stop
FreeForever. No asterisk.
  • Every metering mode, every film stock
  • Works offline after first load
  • Installs to your home screen as a PWA
  • No sign-up, no email, no tracking
iOS / Android native
Stop Native
£2.99One-time. Coming soon.
  • Direct sensor access for slide-film accuracy
  • Home screen widget
  • App Store and Play Store
  • Everything in the web app, plus background reciprocity timer

No subscription. Not now, not ever. A meter is a tool. You buy a tool once.

Answered already

The questions people actually ask.

Any phone with a rear camera and a browser less than five years old. Tested on iPhone 11 upwards, Pixel 4 upwards, and a couple of Samsungs. If your phone runs a Sunday morning Instagram scroll it can run this.
Live metering uses the camera, so yes, the camera costs power. Roughly the same draw as the native camera app. If you lock a reading and put the screen to sleep, draw drops to nothing. Take the reading, pocket the phone, shoot the frame.
Yes. Once the app has loaded once, the service worker caches everything. No signal, no Wi-Fi, no problem. Important if you shoot in the countryside or underground.
Reciprocity tables, zone system overlays, and incident metering with the front camera are all on the list. Colour temperature and flash sync are further out. If it is genuinely useful on a shoot and not a gimmick, it has a chance. If it looks like a feature that belongs in Instagram, it does not.
Because the cost of running a static PWA is basically zero, and a tool the whole community can pick up and share is worth more than a few thousand quid in IAP revenue. The native app is the one that pays for itself.
Stop is a product from Bright Loop Media, a small studio run by Chris Ilabaca. The app was built because the existing options were embarrassing and the existing prices were worse.
stop.

Enough reading about it. Take a reading.

Start metering
Free · No install · No sign-up