I bought the Micro-Nikkor 105mm f/2.8G IF-ED when it was released, returned it almost immediately - a lot of Focus breathing, loss of focal length when up close. lots of CA and slow auto focus.
Is this worse than the older AF 105/2.8 micro?
The AF micro focuses to 0.314m which is the same as the AFS VR version. This suggests they have a similar amount of focal length shortening at close range, even though they focus using entirely different methods (extension+CRC vs IF). I estimate the focal length of the AF micro reduces to less than 80mm at 1:1.
The AF micro has no ED elements so it also shows CA, not sure how it compares with the AFS version?
The focus speed of the AF micro is not fast, but that is common for macro lenses which have such a large focus range. Especially since it focuses by extension with CRC - there are at least two groups of elements moving, some move a long way, so the AF motor has to work hard to focus the lens. Surely the AFS micro with IF focusing is quicker? I find the focus speed of the AF micro to be adequate, especially with the focus limiter turned on.
I think the focus speed is also helped by keeping the manual focus throw short - only 180° from infinity to 1:1. The AFS micro has focus throw of 270° - 1.5x greater, which should make focusing at far distances easier. For comparison, the AIS 105/4 micro has a focus throw of 300° to 1:2, which means it would require 600° to get to 1:1 - more than twice the AFS version!
The AF micro has harsh background bokeh and only 7 straight-edge aperture blades, so the overall rendition is harder and more angular. I understand the AFS 105 micro has smoother background rendition, and also 9 rounded aperture blades so bokeh balls are rounder.
The AF micro is at least lighter and more compact, although it does increase in length when focused close. It also has a manual aperture ring so can be used with manual adaptors like the PK-13 or PN-11 (with good results!)
Besides this, the AFS 105 VR micro does seem to be better than the AF version in some respects, so I am not sure why there are so many negative opinions about it? (disclaimer - I have the AF 105/2.8 D micro, and have never used the AFS VR version)