What is Iris Diffraction Fringe, and what does it do? It doesn't seem to change the look of the shot, no matter what you set it to, and it doesn't seem to be documented in the help or anywhere else on the web.
Diffraction Fringe: Creates a halo around the edge of an iris that simulates light bending, concentrating around the edge of the iris blades. When set to 100, a natural normal halo that is based on the area represented in the shape of the blur is visible. At 500, all the energy of the blur is pushed from inside the blur to the ring/halo. This effect, in essence, emulates a catadioptric lens.
More info about the Camera Lens Blur effect: http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103a9d3c597-7bad a.html
More on Camera lens optics: http://en.wikipedia.org/wiki/Lens_(optics)
Thanks Kevin. Can you add this to the 3D Camera settings help?
Also, that's what I thought it should do, but I haven't been able to get it to work yet. If I take a detailed picture into 3D and throw the camera way out of focus, and switch the bokeh to say, hexagon, I get lots of big hexigons. But no matter what I set the Diffraction Fringe to, it doesn't seem to affect the look of the hexagons in any way. I can set it to 0, take a snapshot, and set it to 500 and the before/after looks the same. I don't see any brighter fringe.
Are there any gotchas we should know about? Any special way the comp has to be set up for Diffraction Fringe to have an effect?