I rented the AF Nikkor 85mm F1.4D and the AFS Micro Nikkor 105mm F2.8 VR over the weekend to try them out. Unfortunately, due to poor weather I was unable to shoot as many pictures as I had hoped. Nevertheless I was able to take some test pictures comparing the bokeh of the three lenses. The tests can be seen at:
Flickr Set 1
Flickr Set 2
Following are my general observations.
The 85mm has a very nice bokeh at F1.4, and it is sharp enough to be used at this aperture. However, there are color aberrations that are visible at maximum aperture. I found that it was difficult to get accurate focus on moving targets (a child) with this lens and the D300. Focusing wasn't slow as such, but somehow the camera did not track very well. This could be a user error as I am not used to taking action pictures. The lens is very well built, and is made of metal. I found that shooting subjects with a bright background created a loss of contrast due to flare. The lens I was using has a serial number 213792 and appeared to have been well used; so this could be just an issue with this sample.
Overall I was happy with the 85mm F1.4 but main concerns are ability to get correct focus and the color aberrations at maximum aperture.
The 105mm Micro VR is a huge lens. It is amazing how big it is compared to my 105mm F2.5 manual focus lens. It is fat and ugly, and looks too large on my D300. The lens appears to have at least part metal build; the focus is very fast at normal distances. The AFS motor just zips into focus; it is much faster than the 60mm F2.8 AFS lens, and the 50mm F1.4 AFS. Perhaps the size of the AFS motor makes a difference to the speed. This was my first experience with a VR lens; I was surprised to hear noises coming out of the lens when VR was enabled. For the test shots I disabled VR. I think VR is useful but I worry that it may make the lens more susceptible to break downs in the longer term. I also feel concerned that a VR lens by its nature is likely to suffer from centering problems, as the VR unit has to move up/down inside the lens.
From a bokeh point of view, I found that the 105mm Micro lens has a smooth bokeh, which can challenge the 85mm F1.4 at equivalent apertures. Of course, the 85mm has a larger aperture, which allows it generate the best bokeh (when used at F1.4) amongst the three lenses. The 50mm F1.4 generates the worst bokeh, as can be seen from the sample pictures.
The 85mm has the best build quality of the lot, and I hope that Nikon does not replace it with a more plastic bodied lens. As the construction is relatively simple and lacks a focusing motor, I presume that this lens is also the most robust and likely to survive the longest.