Hey folks, I won't pretend to be an expert on DOF. However, aside from its quickness, what's the hubbub all about regarding the 110/2.8? The 'portrait' lens? I ask because I have an RZ 90, and RB 65/180mm lenses. The 90 is 3.5 and I wonder how much more control the 2.8 gives me as I seem to get decent enough depth at 3.5. The 110/2.8 isn't cheap - trying to figure it out!