Profiles are interpolated in focal length (vignetting also in aperture and
focus distance), scaled by crop factor, and converted by least squares to the
DNG WarpRectilinear / FixVignetteRadial polynomials the pipeline already
applies. The lensfun database (CC-BY-SA) is only read from a directory the
user supplies; nothing is bundled.
Sources: lensfun's published database format and lens calibration
documentation (no lensfun code read), PanoTools wiki (a, b, c distortion
model), DNG specification 1.6 (WarpRectilinear, FixVignetteRadial);
interpolation and fitting: own design.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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