LiDAR Camera How to measure distance with iPhone LiDAR in the dark
Point the centre of the screen at the object, that's really all there is to it. In LiDAR mode, LiDAR Camera shows the distance to that point in metres with one decimal, coloured green, yellow or red, with a hint such as Optimal range ✓. It works in the dark because the LiDAR Scanner brings its own light with it. The readout is a PRO feature, open to everyone during the first 7 days.
★ 4.2 (9) Can you measure distance with the iPhone camera?
Not really, no, it can only guess. A LiDAR Scanner or the Face ID depth camera actually measures distance, by timing infrared light it sends out itself. That's why LiDAR Camera shows a number only in LiDAR mode and the front TrueDepth Night Vision view, never in Normal mode.
How to measure distance in LiDAR Camera
- Open the app on a device with LiDAR; it starts in LiDAR mode. On a Face ID device without LiDAR, use the front depth view.
- Make sure PRO is active: during the first 7 days it is, and afterwards it needs a purchase.
- Aim so the circle in the middle of the screen sits on the object.
- Hold still for a moment. The distance appears under the circle, for example 2.5 m, with a colour and a hint.
- If it shows
--, move to a matte part of the object or step closer.
How the app works out the number
In LiDAR mode the app takes a small block of depth points around the centre of the frame, drops those ARKit marks as low confidence and anything under 5 cm or over 10 m, and uses the middle value, the median. One stray point cannot drag the reading off. The shown value is rounded to one decimal.
| Step | Values (m) |
|---|---|
| Confident samples | 2.41, 2.44, 2.46, 2.47, 2.52, 2.60, 0.02, 12.00, 2.45 |
| Kept (between 0.05 and 10 m), sorted | 2.41, 2.44, 2.45, 2.46, 2.47, 2.52, 2.60 |
| Median | 2.46 |
| Shown | 2.5 m, yellow, Optimal range ✓ |
The front TrueDepth view averages a smaller block of points instead of taking the median. Rounding, colours and hints all work the same way, so once you understand one view you understand both.
What the colours and hints mean
The colour depends on the shown value: green under 1.0 m, yellow from 1.0 to 2.9 m, red from 3.0 m. The hint tells you whether you are in the sensor's comfortable range: 0.3 to 4.0 m for rear LiDAR, 0.2 to 2.0 m for the front depth view.
| Camera | Measured | Shown | Colour | Hint |
|---|---|---|---|---|
| Rear LiDAR | 0.24 m | 0.2 m | Green | Too close |
| Rear LiDAR | 0.28 m | 0.3 m | Green | Optimal range ✓ |
| Rear LiDAR | 0.95 m | 1.0 m | Yellow | Optimal range ✓ |
| Rear LiDAR | 2.96 m | 3.0 m | Red | Optimal range ✓ |
| Rear LiDAR | 4.04 m | 4.0 m | Red | Optimal range ✓ |
| Rear LiDAR | 4.06 m | 4.1 m | Red | Move closer for better results |
| Front TrueDepth | 0.14 m | 0.1 m | Green | Too close |
| Front TrueDepth | 0.24 m | 0.2 m | Green | Optimal range ✓ |
| Front TrueDepth | 2.06 m | 2.1 m | Yellow | Move closer for better results |
Red doesn't mean danger. It only marks 3 m and up. Move closer for better results just means you've drifted past the sensor's most dependable range.
Tips for a steadier reading
- Aim at a matte, light surface: a wall, a box, a door. Glass, mirrors, black fabric and polished metal return little light.
- Hold the phone steady for a second; the value updates live.
- Stay inside the good band: 0.3 to 4.0 m with rear LiDAR.
- For point-to-point lengths, like the width of a doorway, use Apple's Measure app. LiDAR Camera reads one point: the centre of the frame.
Questions and answers
Is the distance readout free?
Can it show feet and inches?
Why does it show --?
Does it work without LiDAR?
You might also like
- Which iPhones have LiDAR, and what the app does on yours · LiDAR Camera
More LiDAR Camera guides
- How to use your iPhone as a night vision camera
- Can iPhone LiDAR see in the dark? Using the LiDAR depth view
- Which iPhones have LiDAR, and what the app does on yours
- Thermal camera app for iPhone: what a filter can and can't do
- How to record night vision video on iPhone
- How to add a night vision filter to a photo on iPhone
- How to take a silent photo on iPhone with no shutter sound
- Manual camera controls on iPhone: ISO, Shutter, AE Lock and AF Lock
- How to use a self-timer on iPhone to delay a photo
- Can you use an iPhone as a night camera to watch animals in the garden?
- Can you use an iPhone as a night vision camera for a baby's room?
- All questions about LiDAR Camera
- Back to LiDAR Camera