When to Use Vignetting?

A vignette can work to draw the eye to the centre of the image. You can use one when the edge of the image is relatively bright and fights for your attention. Perhaps the main subject in the centre is a bit darker than the surroundings. However you don't want to use a vignette to darken the image too much.

What is a vignette used for?

A vignette is a darker border - sometimes as a blur or a shadow - at the periphery of photos. It can be an intentional effect to highlight certain aspects of the image or as a result of using the wrong settings, equipment or lens when taking a photo.

Do professional photographers use vignettes?

Though some prefer a stronger vignette than others, most photographers can agree that a vignette that works against your composition is not a good use of that effect.