Nikon AF 85mm f/1.4D
compared to
Nikon AF 85mm f/1.8(D and non-D versions)

Outside (with no point light sources in the background):

Out of focus renderings compared: Top left: 85mm f/1.8 at f/1.8. Top right: 85mm f/1.4D at f/1.7.	Watch the slight color shift between the two images! The out of focus areas look very similiar in this situation, no questions asked...
Out of focus renderings compared: Top left: 85mm f/1.8 at f/1.8. Top right: 85mm f/1.4D at f/1.7.	The background in the images is very similiar. I prefer the 85mm f/1.4D renderings but we're splitting hair here. Take into consideration: With the 85mm f/1.4D lens the aperture can be set to f/1.4 and the background gets even smoother.

Indoors at f/1.7-f/1.8 (with point light sources in the background):

Out of focus renderings compared: Top left: 85mm f/1.8D at f/1.8. Top right: 85mm f/1.4D at f/1.7.	With point light sources in the background (Christmas candles) the difference is quite obvious. Take into consideration: With the 85mm f/1.4D lens the aperture can be set to f/1.4 and the background gets even smoother.
Left column: Two crops from the 85mm f/1.8D at f/1.8 image above. Right column: Two crops from the 85mm f/1.4D at f/1.7.	One can clearly see more sharpness with the Nikon AF 85mm f/1.4D. But do you really want to see all those details in the face ...?

Indoors at f/2.8 (with point light sources in the background):

Out of focus renderings compared: Top left: 85mm f/1.8D at f/2.8. Top right: 85mm f/1.4D at f/2.8.	With point light sources in the background (Christmas candles) the difference is very obvious at f/2.8.
Left column: Two crops from the 85mm f/1.8D at f/2.8 image above. Right column: Two crops from the 85mm f/1.4D at f/2.8.	One can clearly see more sharpness with the Nikon AF 85mm f/1.4D even at f/2.8.