OptionalenabledOptionalamountPrimary radial coefficient k1. Negative = barrel (fisheye bulge), positive = pincushion. Roughly -1..1. Default 0.
OptionalsecondarySecondary radial coefficient k2 (higher-order edge correction). Default 0.
OptionalscalePost-distortion zoom. >1 zooms out (shows more, reveals clamped edges on barrel), <1 zooms in to crop the warped border. Default 1.
Radial lens distortion (Brown–Conrady polynomial).