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For a real lens which may interface different media, calculates the axial and the height chromatisms as functions of the refraction indexes, the surfaces radii, the center thickness, the object height and the object position.

When glass references are used instead of refraction index values, the chromatism is calculated using the chosen glass references and in the spectral range going from lam_min to lam_max. lam_min and lam_max are defined in the page General parameters/Wavelengths.