Dave Scotland from CGSwot shows how to add dirt to a lens in After Effects by means of a simple fractal noise to create a dirt map that will be effected when the light of a scene hits the lens.
Check out the tutorial for Creating a Dirty Lens Effect in After Effects here.
from the CGSwot description: Learn how to create a dirty lens effect without any particles or dirt images and use fractal noise to create dirt maps and animate these based on light hitting the lens. Learn how to use motion tracking data for an object which is off-screen…
Great! thanks for sharing
I usually use the optical flares