I have the DSR-450. It tends to shoot a little hot, so I have grown to use zebras and not use auto iris. There is an adjustment on the auto iris that allows up to open/close the auto iris by one stop, but it does not 'hold' - once you power off the camera, you lose that (page 55/56 of the instructions). It looks like the other option is to tweak 'select the automatic iris window'. Any idea where it should be set to? You can adjust it so that you decide where 'light detection occurs'. I shoot educational stuff as well as 'news' stuff. I would like to be able to use (or at least have the option) to use auto iris when shooting b-roll for news. Even inside, under a nice refa light I get hot video if I use the auto iris, which tells me something, somewhere is off.