Light falloff may increase because an image is exposed more at the center of the frame than at the corners. The distance light has to travel from the lens to the sensor is greater at the edges than it is at the center and, therefore, less light reaches the sensor from the lens at those more oblique angles. In addition, some of the outer off-axis light is restricted by the lens barrel, which is known as vignetting. This effect is most common in wide-angle lenses that are used at the initial aperture (i.e., wide-open). Falloff due to vignetting can usually be reduced by stopping down.
- Select an image that you want to correct.
- In the Lens Correction panel in the Lens tool tab, check the profile for your lens that has been selected automatically. Alternatively, from the drop-down menu, search for a similar model or use the generic profile options instead.
- If you have a profile for your lens, set the amount to 100% to result in a completely flat and even-looking image.
- Alternatively, use a generic profile and manually set the desired amount with care. Values higher than 100% are possible and increase the effect of the correction.
- The setting can be saved as a User Preset and applied to multiple images onwards.