The Lens tab contains controls to adjust chromatic aberration, which is commonly seen along the edges of bright areas. The two sliders control either red and cyan or blue and yellow fringing. By moving the sliders to the left, you'll remove either red or blue from the image, while adjustments to the right will correct for cyan or yellow problems, as shown in Figure 7.40.
Figure 7.40. The Lens tab, only in the Photoshop CS2 version of Camera Raw, includes controls to correct chromatic aberration and vignetting in your digital images.
The Vignetting control can correct for darkening seen at the edges of images with some lenses (Figures 7.41a and 7.41b). An alternative use for the control is to add vignetting to draw attention to the center of your image. The Midpoint slider controls how far from the center of the image the vignetting adjustments occur (Figure 7.42).
Figure 7.41a. Wide-angle lenses, especially with filters, can lead to darkening or vignetting at the corners.
Figure 7.41b. Using the Vignette control you can remove or greatly reduce the amount of vignetting in the shot.
Figure 7.42. An alternate use of the Vignette control is to add vignetting to the image, darkening the corners to draw more attention to the center of the photo.