

The Lens Calibration panel provides the following information:
The lens system works by interpolating between valid lens calibration points. Lens calibration is covered in more detail in a separate chapter.
Since it’s difficult to calibrate a target at a focus distance of infinity, in practice the targets are calibrated at focus distances of about 1, 2, 3, 4, 5, and sometimes 7-8 meters away from the camera sensor location. For focus distances over this, the virtual focus distance is interpolated linearly from the last real focus distance (obtained from the nearest valid calibrated point) to the infinity focus distance value shown above.