HI Gerrit,
How are you navigating into 3d space? I find using cameras to be useful only when preparing 3d perspective views for presentation.
Otherwise I use either the standard orthogonal & isometric views which, I believe, will center on the some weighted center of all the objects on the visible layer,
or the shift-c flyover tool which centers the 3d rotation on one of 4 origin modes. (selected point /selected object / ground plane origin / working plane origin)
hth
Brian