105mm f/1.8 AIS Nikkor at f/4. Not as buttery smooth as my 85mm f/1.4 AIS, but no slouch either! It is not apparent in this smaller version, but her right hand is actually little out of the depth of field and is a little soft, but then again, this is just barely 1 stop down and Erin was about 12 feet from me or so. I prefer to use longer lenses for their shallower depth of field. It is not unusual at all for me to use my 180mm f/2.8 ED AIS for outdoor portaiture. It is sharp as a razor and the depth of field at f/4 is pretty narrow and with a very nice bokeh.
And the 300mm f/2.8 ED-IF AIS at f/4. Smooth as buttah!