My Nauticam viewfinder also "wobble" slightly when the viewfinders are on the housing above the water. But when underwater the water pressure, and also the negative internal pressure of my vacuum seal leak detector, seem to hold the viewfinder in place better. Nauticam uses an o-ring to hold the viewfinder in the housing. And has two o-rings on the viewfinder "tube". I believe it is these o-rings that are the cause of the viewfinder wobble. I've been down to depths of about 200' repeatedly with the Nauticam viewfinder on my Subal ND800, via an adapter, and never had a drop of water get in the housing.
- pmooney likes this