Aim
Choose Average, Center or Spot, and tap the picture to put the spot on what matters.
Light Right
A light meter for film photographers.
Light Right turns your iPhone into a reflected-light meter for manual film cameras. Point it at the scene, choose what to expose for, and read the aperture and shutter speed off two dials, then set them on the camera in your other hand.
How it works
Aim. Lock. Hold.
Three steps between the scene and the camera, all on one screen.
Lock
Lock the aperture or the shutter speed and the meter works out the other. Lock both, and a needle shows how far off you are.
Hold
Tap the reading or press a volume button to freeze it, then set your camera at leisure.
What it does
It meters like a meter.
Average, Center or Spot, placed with a tap. Two dials that each follow the meter or stay where you lock them, and a needle like the one in a viewfinder.
Metering
Three modes, two dials, one needle
Average meters everything between the controls. Center meters a weighted area in the middle. Spot reads about 5° of the scene, wherever you tap. What is framed on screen is what is read.
The needle runs two stops either side, in thirds. Within a third of a stop counts as correct; past the end, it pins with an arrow and writes the true difference beside it. The same on iPad, with its rear camera.
Hold
Meter, then turn to the camera
Tap the reading, or press a volume button or Camera Control, and it holds. The reading is marked HELD and the picture freezes with it, so you can see what you metered while you set the camera.
The dials, film speed and compensation still work against a held reading. Tap a new spot, change mode or turn the phone to let it go.
Film
Box speed, pushed or pulled
Film speed from ISO 12 to 6400 in the standard third-stop series, each with its DIN equivalent, or any exposure index typed in for film pushed or pulled.
Apertures, speeds and compensation step in full, half or third stops. Compensation runs to ±5 stops, is flagged on the meter while it’s set, and stands in for a filter too: a red filter is about +3.
Calibration
Make it agree with a meter you trust
A phone’s camera is tuned for pleasing photographs, not the standard a handheld meter is built around. Calibrate once against a grey card and every reading after carries the offset.
The offset is kept in tenths of a stop, and can be nudged or reset. Step by step under Calibration in the help below.
Long exposures on B
Past the camera’s slowest marked speed, the shutter dial carries on to 60 seconds and tells you how long to hold B open. That’s the metered time, before your film’s reciprocity correction.
Quick in low light
The live view shows the scene as it is, whatever the dials say, so it stays quick in the dark. The needle is what shows the exposure.
Says when it’s unsure
Settling… while the phone adjusts to a new scene, and a warning when a reading goes past what the phone’s camera can measure directly and is only approximate.
The numbers
Rounded for display, and only for display.
Apertures and shutter speeds are kept at their exact values, and only shown as the figure engraved on the barrel or the dial.
f/8 · 1/250f/11 · 1/125f/16 · 1/60f/22 · 1/30
Cameras
It knows your camera.
Pick a camera and turn on “Only offer its settings”, and the dials keep to the speeds and apertures actually engraved on that body, down to a Compur dial’s irregular 1/25 and 1/50.
Bundled or your own
Common bodies are ready to go
A set of common cameras comes bundled, so most people never have to set one up. If yours isn’t there, duplicate the nearest one and change it, or build your own from scratch.
Tick every speed marked on the shutter dial, irregular dials included, say whether it has a bulb setting, and set the widest and smallest apertures of the lens you have mounted. A bundled camera’s apertures are only its kit lens, which is why Duplicate & Customize is there.
Price and privacy
It asks nothing of you.
Light Right reads the light through the camera, and that is all. Nothing is photographed, saved or sent anywhere, and the App Store privacy label reads Data Not Collected.
Free, with nothing to unlock
Every feature on this page is in the free download. No ads, no subscription and nothing held back.
No account, no analytics
Nothing to sign up for and nothing watching what you meter. The app makes no network requests of its own.
The camera measures light
Camera access is used only to read the scene. The picture on screen is never saved, and never leaves the device.
Works without a signal
Metering happens on the phone, so it works in the field with no connection at all.
Help
Help with Light Right.
For when the app is open and the camera is in your other hand. Every control is named as it appears in the app.
Getting started
Allow camera access when asked. The camera is only used to measure light. Then open Meter Settings and set the film speed.
- The panel at the bottom is the meter card. At its top left, a button shows the camera and film speed and opens Meter Settings. At the top right is the reading in EV, with the metering mode above it.
- Below that, the verdict (Underexposed, Correct exposure or Overexposed) and a needle two stops either side, in thirds. Within a third of a stop counts as correct. Past the end, the needle pins with an arrow and the true difference is written beside it.
- Then the Aperture and Shutter dials. Auto beside a dial means it follows the meter.
Metering modes
Average meters everything between the controls.Center meters a weighted area in the middle. Spot meters a small area, about 5° of the scene, wherever you tap. What is framed on screen is what is read.
Locking the dials
- Tap a dial’s center value to lock or unlock it. Tap a neighboring value, or spin the dial, to set it; either locks it too.
- Neither locked: the meter picks the pair, keeping to your last aperture when it can.
- One locked: it works out the other.
- Both locked: the needle shows how far off you are.
- The line under the dials always says which state they’re in.
Holding a reading
- Tap the reading, or press a volume button or Camera Control, to hold it. It shows HELD, and the picture freezes so you can see what you metered.
- The dials, film speed and compensation still work against the held reading.
- Tapping a new spot, changing mode or turning the phone lets it go.
- While the phone is still adjusting after you re-aim, the verdict reads Settling… and the reading fades. Wait for it to come to rest before holding.
Long exposures
When the meter calls for longer than the camera’s slowest marked speed, the shutter dial carries on to 60 seconds, markedB 8s and so on, and the hint reads Set the shutter to B · hold it open for 8s.
This is the metered time. Film loses sensitivity over long exposures, which is reciprocity failure, so check your film’s data sheet and add its correction. The app doesn’t do this for you.
With neither dial locked, the meter opens the lens before it goes to B, so you only need a cable release when there’s no other way.
Film speed and compensation
- Film Speed in Meter Settings offers the standard third-stop series from ISO 12 to 6400, each with its DIN equivalent.
- Enter Exposure Index… takes any speed, for film pushed or pulled.
- Compensation gives every reading deliberately more or less light, up to ±5 stops, and is flagged on the meter when set. Use it for a filter, too: a red filter is about +3.
- Increments sets whether the dials and compensation step in full, half or third stops.
Your camera
- In Meter Settings, choose a Camera and turn on Only offer its settings to limit the dials to what that body can actually be set to.
- Manage Cameras lists the bundled bodies and your own. The bundled ones can’t be edited; choose Duplicate & Customize to make your own copy.
- For your own: tick every speed marked on the shutter dial (irregular dials are fine), say whether it Has a bulb setting, and set the Widest and Smallest apertures of the lens you have mounted, plus whether its ring clicks in full, half or third stops.
Calibration
A phone’s camera is tuned for pleasing photographs, not the standard a handheld meter is built around, so Light Right may read a little differently from a meter you trust. Calibrating once fixes that for every reading after.
- Open Meter Settings → Calibration.
- Point both meters at the same evenly lit subject. A grey card filling the frame is best.
- Under Trusted Meter, enter what the other meter says: either the aperture and shutter speed it recommends at your film speed, or its EV at ISO 100.
- Tap Match This Reading.
The offset is then shown and can be nudged a tenth of a stop at a time, or reset to zero. A positive offset makes the app read brighter, giving less exposure.
Messages
What the app might tell you, and what to do.
- Camera Access Needed
- Camera access is off. Tap Open Settings, or go to Settings → Privacy & Security → Camera and turn on Light Right.
- Settling…
- The phone is still adjusting to a new scene. Wait for the reading to come to rest.
- Very low light - reading approximate
- Darker than the phone’s own camera can measure directly. The reading is extended past that point, but treat it with care, and bracket.
- Very bright - reading approximate
- The same, at the bright end.
- Too dark for this camera
- Even the widest aperture and slowest speed your camera allows would underexpose. Open up, use a faster film, or go to B.
- Too bright for this camera
- Even the smallest aperture and fastest speed would overexpose. Use a slower film or an ND filter.
- Camera in use by another app
- Another app has the camera. Close it and come back.
- Camera unavailable while multitasking
- On iPad, the camera can be unavailable while other apps share the screen. Make Light Right full screen.
- Camera paused to cool down
- The device is too warm. Let it cool, out of the sun.
- No camera available on this device
- Light Right needs a rear camera.
Questions
Will it work with my camera?
With any camera whose aperture and shutter you set by hand. Choose Any camera for the full scale, or set up a profile for yours.
How accurate is it?
That depends on the phone. Calibrate it once against a meter you trust, especially before shooting slide film, which forgives less.
Why doesn’t the picture get darker or brighter when I turn the dials?
The live view shows the camera as it is, whatever the dials say, so it stays quick in low light. The needle is what shows the exposure.
Can it do incident or flash readings?
No. It is a reflected-light meter, and a phone can’t do either properly without extra hardware.
Does it work on iPad?
Yes, with the rear camera. Not on a Mac or Apple Vision Pro, which have no rear camera.
Is it really free?
Yes. No ads, no subscription and nothing to unlock. If it helps you get an exposure right, there’s a tip jar at the bottom of Settings, from a Small Tip to a Roll of Film. Tips are entirely optional and unlock nothing.
Does it work without a signal?
Yes. Only the tip jar needs a connection.
Is anything I point it at saved?
No. Nothing is photographed, saved or sent.