Simulating diffusion filters with PhotoShop

[Scott_M]

I am still relatively inexperienced with PhotoShop. Is there a way to simulate shooting through a diffusion filter? [img]/ubbthreads/images/graemlins/confused.gif[/img]

When shooting with film I usually prefer to wait until the darkroom to use a diffusion filter (A Cokin 083 works perfectly under the enlarging lens). That way I have a sharp negative, which leaves me more options.

How do we simulate this effect with PS? There has to be more to it than Blur or Smart Blur.

SM