Apply the Vignetting effect to reduce the brightness or saturation of your clip at the periphery compared to the center. Vignetting adaptively adjusts the exposure of your clip, preserving the original contrast and creating a more visually pleasing effect. See Vignetting in New special effects.
To apply a Vignetting effect, select the clip in the Expert view timeline and apply the effect from the Advanced Adjustments category in the Effects panel.
Use the Applied effects panel to adjust the following properties of the Vignetting effect:
Size
Lower values apply the size adjustment to a larger area away from the corners. Higher values restrict the adjustment to an area closer to the corners.