The Lens Distortion filter provides a way of correcting distortion caused by the curvature of a camera lens. It's especially useful for correcting barrel distortion (where straight edges are bowed outwards), or for correcting pincushion distortion (where straight edges are bowed inwards).
This filter can be applied as a non-destructive, live filter. It can be accessed via the Layer menu, from the New Live Filter Layer category.
The following settings can be adjusted in the filter dialog: