The red row is what the meter suggests. Tap an aperture to lock it, or a speed to lock that instead. Tap the locked one again to release it.
Logbook
Every tap of the red circle saves the metered frame to the roll you're metering for. Tap a frame to edit its notes. Everything stays on this phone until the app has accounts and sync.
My cameras
My films
How this was measured
The phone's lens has a fixed aperture. With the exposure locked, the page knows exactly how much light the sensor was given, so the brightness of the metered area tells it how bright the scene is.
- N
- Phone lens aperture (fixed, set in Setup)
- t
- Phone shutter time in seconds, as the camera reports it
- S
- Phone ISO, as the camera reports it
- Y
- Average brightness of the metered area, converted back to linear light (0–1)
- 0.18
- Mid-grey: a meter assumes the scene averages out to 18% grey
- k
- Response slope from the linearity test (1 = perfectly linear)
- C
- Calibration offset against your camera's meter
Then for your film: EV = EV100 + log₂(ISO/100) and for each aperture t = N² / 2EV.
What we're finding out
Can Chrome lock the exposure? Does brightness follow the exposure? Does it report live auto-exposure values? How far off is it from a real meter? Run 2 and 3, do a few calibration points, then share the report.
1 Camera & controls Not run
- Status
- Start the camera first
2 Exposure lock Not run
Fill the view with an evenly lit, plain surface (a wall, a grey card, a sheet of paper in shade). Hold still. The page steps the shutter, then the ISO, and checks that brightness follows: one stop more light should double it.
3 Live auto-exposure Not run
Switches to auto exposure for 10 seconds. During that time, point at a bright window, then at a dark corner, then back. The page checks whether Chrome reports the shutter and ISO the camera picks.
4 Calibration No points
Done in the Calibrate tab against your metered camera.
Report
Log
Calibrate
1 · Exposure. Point the phone and your camera at the same evenly lit, plain surface, filling both views. Set the same ISO and lens here as on the camera. Enter the camera's aperture and shutter, and what its meter shows at those settings (on a Sony in M mode, the M.M. number; 0.0 if it's centred).
Repeat in bright sun, open shade and indoors. If the offset stays the same at every brightness, one number calibrates the meter.
2 · Framing. Compare the preview with your camera's viewfinder at the same lens. If the preview shows more or less than the viewfinder, adjust the phone's focal length in Setup until they match. That makes the metered area match what the lens sees.