Live Mode is where the app opens. The camera runs continuously, and the three spot meters track the brightest, middle and darkest regions of the scene, smoothed so they glide rather than jump.
The reticles
Three crosshairs are drawn on the preview, each labelled with the EV at that point:
| Reticle | Colour | Region | Zone |
|---|---|---|---|
| Highlight | Red | The brightest | VII |
| Midtone | Green | The middle tone | V |
| Shadow | Blue | The darkest | III |
They are found automatically and move as you pan. In live mode they cannot be dragged — take a snapshot first (see Offline Mode).
A dot (•) beside an EV value means the reading has been corrected to a reference meter. See Calibration.
If red and green are hard to tell apart, switch the BW / Color toggle to BW. The reticles become white, mid-grey and dark-grey, and the High / Mid / Shadow text labels in the readout continue to name each reading. VoiceOver reads each reticle in full — “Highlight spot meter, EV 12.3”.
The controls
ISO — a scrollable column from 25 to 102400, default 100. Every EV reading is relative to it: doubling the ISO adds 1.0 EV to all three, halving it subtracts 1.0. Set it to the film you are shooting before you read anything off the screen. The choice persists across restarts.
Film format — the frame you are working in: 35mm, APS-C, 6×6, 6×7, 6×9, 4×5, 5×7, 8×10, or a custom size. The preview is cropped to that format’s angle of view for the focal length you pick, so you meter the frame you will actually expose rather than whatever the iPhone lens happens to see.
- Focal length — a list of common lengths for the chosen format, or Zoom to reveal a continuous slider.
- Orientation — horizontal or vertical framing.
BW / Color — switches the preview between colour and black-and-white. It changes the display only; the EV readings are identical either way. Useful for seeing tonal separation without being distracted by hue, and for making the reticles readable if red and green are hard to distinguish.
Photo library — opens the picker. Choosing a photo takes the app into offline mode with that image instead of a snapshot.
Shutter — the white circle. Freezes the current frame, cropped to the selected film format, and enters offline mode.
EV readout — the three current values, colour-coded. With Fancy Look turned on in Settings, this becomes an analog meter dial instead of a plain list.
Metering mode
Set in Settings, this decides how the snapshot is captured:
| Mode | What it does |
|---|---|
| Fast (Video) | Linearizes the live video stream. Continuous readings and an instant snapshot. |
| RAW (Single Shot) | Captures a single DNG on snapshot for the most accurate measurement. Slower by the length of one capture. |
RAW is the more faithful measurement because it reads the sensor before the video pipeline has processed it. On a device that does not support RAW capture the app falls back to the video stream rather than failing.
The top bar
- ☰ — the menu: Rolls & Memos, Settings, About.
- ? — context-sensitive help for whatever is on screen.
- LIVE appears at the top left in offline mode only, and returns you here.