Lens vignetting is also more common with wider angle lenses and is particularly noticeable if the subject you are photographing contains what should be an even shade of tone or color. For example, if you are photographing a landscape with a large expanse of sky or viewing a photograph taken against a plain wall, it is in these types of situations that you may become more aware of any lens vignetting problems that can be seen as a darkening of the image toward the corner edges.
The Vignettes panel consists of two sections. The first contains the Amount slider, which can be used to lighten the outer corners relative to the center, and a Midpoint slider. By using these two controls, you can usually find an optimum setting that will correct for the light falloff in a photograph, such as in the landscape photograph example shown on the right. Most of the correction is done by first adjusting the Amount slider, followed by a fine-tuning with the Midpoint slider to balance the vignette from the center to the edges. With these two slider controls, you should be able to precisely correct for the vignetting in almost any photograph. Once you have found the settings that are right for a particular lens, you might want to save these Vignette panel settings as a preset that can be applied to other pictures shot using the same lens focal length and aperture.
The Vignette Amount and Midpoint sliders can also be used to compensate for the light falloff in studio lighting sets. In Figure 6.51 you can see an example of a studio shot in which the model was photographed against a white background using a wide angle lens. Although I tried to light the background and foreground as evenly as I could, there was some inevitable light falloff toward the edges of the frame. In situations like this it can be useful to adjust the Lens Correction sliders so that the darker corner edges of the frame are lightened slightly. You might even want to copy what I did with this set of photos and create a default setting for all the photographs that are taken using a particular lighting setup that includes lens correction adjustments.
- Vignetting is always more noticeable in photographs where there is a large area of flat continuous color or tone, such as a deep blue sky. The increase in darkness toward the corner edges is quite noticeable here.
- Here I applied some lens correction adjustments via the Detail panel, in which I used a positive Amount setting to lighten the corners and fine-tuned this anti-vignetting adjustment by tweaking the Midpoint slider.
Just as you can use the Lens Correction sliders to remove a vignette, you can use them to apply a vignette as well. I often like to deliberately darken or lighten the edges of a photograph and use the Lens Correction sliders as basic dodge or burn tools for the corners of a photograph.
In Lightroom 2, we now have Post-Crop vignette controls (see Figure 6.52) that can do the same thing as the Lens Corrections sliders, except they are applied relative to the proportions of the cropped photograph and feature a Feather slider that allows you to soften or harden the vignette edge. This is very much a tool for making creative effects. To give you some inspiration I have taken the photograph shown in Figure 6.53 and applied four different Post-Crop vignette settings (Figure 6.54). The main thing to point out here is that the Post-Crop sliders work just as well on uncropped images and the ability to apply both a global and a local vignette means that you can even experiment with combinations of the two settings when editing a cropped photograph. For example, in the bottom-right image in Figure 6.54, I combined a negative global vignette with a positive Post-Crop vignette.