Turning the automatic iris on and off doesn't, in itself, have any effect on the blacks. The iris only works when the scene brightness drops by a certain level - when the iris 'sees' this happen, it closes down to give the appearance of better blacks. To test it you need to do something to make the on-screen scene go from mixed black and white to just black. One suggestion has already been made, which is to set the BD player to a black scene, with it on pause, and then put up the Epson menu. You will hear (and see) the iris working as you show and remove the menu.
It's nothing to do with the throw - I am throwing 9 feet and my iris is working perfectly.
Thanks. I know it's working, but what I'm saying is last night as I was playing around with it, the picture looked a little better with it off. Do you notice a difference in your blacks with it on? Also, if it is "off", does that mean the iris is fixed at its widest point?
OK. I assume you can hear it working if the room is very quiet? I can hear mine easily if there is no content playing (it is almost directly above my head - about 4 feet up).
The difference I see when auto iris is engaged is just what I'd expect - deeper perceived blacks. It is quite noticeable on certain scenes and under test of the sort described above. The light level drops noticeably as the iris engages,. This is with the iris in high speed mode - I assume yours is in HS mode when you are using it?
I believe that when auto iris is disengaged via the menus that the iris will be wide open, but this is speculation. It could be wide open or less than wide open and it will still shut down dramatically when the right picture conditions present themselves. The only way to test it is with dynamically changing conditions - you can't see any effect on a static picture.
What do you see when doing the 'menu on screen and off' test? Do it both with auto iris on and off - you should see the blacks get darker when auto iris is on and you exit the menu, and you should see no difference at all when it is off.