You can calibrate them with the calibrate menu and settings for yourself.* Pro version added Features:
- Width and Area can be measured
- Quick Shutter
- Portrait mode
- Camera Zoom
- Virtual Horizon
- No ads
* Now, 3 tools for distance were completed.
1) Smart Ruler (short, by touch) : 1-50cm
2) Smart Measure (medium, trigonometry) : 1-50m
3) Smart Distance (long, perspective) : 10m-1km* Do you want more tools?
Get [Smart Tools] package.For more information, see the manual, Youtube video and the blog. Thank you.