A simple curve does the majority of the work, but if you push it just a bit further than what I did here, you really start to see the vignetting... which might be an effect you're after.
foggy copy by namethatnobodyelsetook, on Flickr
A simple curve does the majority of the work, but if you push it just a bit further than what I did here, you really start to see the vignetting... which might be an effect you're after.
foggy copy by namethatnobodyelsetook, on Flickr