When they invented the sensor roller you speak of they started calling Rolleis "Automat" The Automats start pretty early in the Rollei line. It isn't only the 2.8s that have the auto feeler roller.
Originally Posted by rolleiman
When they started making the 2.8 GX they got rid of the auto feeler. Now in the FX/FT/FW/Fx-N there is no auto feeler, you merely line up the arrow with the red dot just like the T. As far as I am concerned it is good riddance. IMO the auto feeler had almost no value beyond being a selling point. I trust the red dot and arrows in my FX far more than the auto feeler in my F.