Nodes

Lens Grid Calibrate

Solve a lens from checkerboard photographs.

The most reliable lens data doesn't come from the shot at all. It comes from photographing a checkerboard with the same lens.

Takes Images from an Images Folder, outputs Lens Data.

Shooting The Grid

Print a checkerboard and take 15 to 30 stills at the same focal length. Fill different parts of the frame, especially the corners where distortion is strongest, and tilt the board at a range of angles.

Board dimensions are detected automatically, so the legacy Columns and Rows fields can be ignored.

Settings

Square Size (mm) is the physical side of one printed square. Measure it rather than trusting what you meant to print.

Sensor Width (mm) converts the solved focal length from pixels to millimetres.

Focal (mm) locks the focal length to a known value, leaving only distortion to solve. Zero solves it.

Camera Details and Lens Model pick which model to fit.

Results

The node reports the solved focal length in pixels and millimetres, the distortion coefficients, the RMS error and how many images were usable.

If it reports far fewer usable images than you gave it, the board wasn't detected in the rest. Usually too small in frame, too blurry, or cut off at an edge.

Where It Goes

Lens Data feeds Auto Track, which then solves with a known lens instead of guessing, or Lens Distortion directly.

See Also

Advanced Tracking covers grid shots alongside the other lens calibration options.