Manual Iris control?
 

Do these camera's have it?

If they do, i dont think the one on my camera is working.

Manual Iris control is the smallest ring on the lens, closest to the body BUT you need to turn the M/A switch on the zoom handle (under your pinky finger if your hand is in the grip) to M(Manual) for it to stay. And you can also use the little tiny button on the top of the handgrip for Push-Auto.

D'oh! Thats what I haven't pressed, the button near the hand grip!

Thanks Shaun, its working now. I cant believe i missed the simplest thing ;-/

Don't worry, i've seen bigger blond moments... It's not like you showed up for the final scens of a luxury liner disaster movie with 150 extras, 100 crew, barge, 8 life boats on the open ocean, and then someone figured out the Panaflex cameras where back at the studio, 4 hours away. So don't feel bad over a silly little iriis issue. :)

Alex... is that a true story about JC's boat movie?!?!?!?

yup... that or it was in the van that broke down and was left on the side of the road on the way to the harbor an hour behind us. Never did get a straight answer, but we did feel silly sitting out on the open ocean for a couple of hours while while the camera crew played "who's on first" but yeah, things happen. It might have even just been the film magazines. Who knows. I can only imagine the blood draining from whom ever was supposed to have had them, and realized they didn't.