How to Create a Vignette in Photoshop
On this quick and simple video tutorial, Photoshop product manager Bryan O’Neil Hughes takes a look at a few easy ways to add (but also remove) vignette, or dark corners into your images.
Vignette is typically considered an unwanted optical problem. It happens because the corners of the lens are not capable of fully covering the sensor of the camera. When shooting with a full frame lens on a crop sensor you typically see far less vignette but when shooting with some full frame lenses on a full frame sensor (or crop lenses on a crop sensor) you might be able to see some vignette – especially when shooting wide open (with a lower f number).
Getting back to the video, Hughes start with talking about adding and removing vignette using Camera Raw but then goes on to show how to get a similar result using Photoshop itself.