[midjji]

Looking through the comments People are confusing the lens models, with the nl estimator used, with the framework for calibrating cameras. There is no such thing as the OPENCV lens model. There is such a thing as the brown lense model as implemented in opencv.

The lense model is the parametrized approximation of the lense function. Picking the right one matters for ideal accuracy.

The estimator takes observations which constrain the parameters of the lens function, and find the parameters.

The framework helps you create those observations.