Suddenly I noticed the iris ring is giving me a hard time. It was always very smooth, now it takes some power to turn it. When I use the iris ring in auto mode, it doensn't properly turn anymore to compensate exposure. any idea what might causing this?

Quick other question ; Can one use the Ewa Marine under water housing for the EX1 also for the EX3? Anybody knows?

Sounds like it's time to send it into Sony for a repair. Forcing it could make it worse!

If you are using Auto Mode, then the Iris ring will be powered, just like the Zoom control when you turn the zoom servo On, don'r force either. Try turning the Auto Iris Off and see if it is still stiff.

Mine has always been a little stiff, just not as smooth as a SLR iris with just a little drag or 'momentum' to it. I've thought that was the normal behavior. There is definitely some mass to it and the auto is disengaged. It's really hard to turn with Auto On and the the ring will turn back to what it thinks is the correct setting in that mode.

Just checked my (NEW) EX3 lens using Auto Iris ON and OFF, and there is no drag in either mode.