Transitions For Premiere Pro CS4

[Kevin Gallagher]

I'm using PP on a PC and am looking for a transition that resembles a lens iris winking open and closed with a shutter click. The only iris transitions in CS4 that I can find are more like plain black shapes. If I was more experienced at this I'd try and tinker something together using After Effects but I'm just starting to get a handle on using Premiere Pro.

  Thanks, Kevin