The 28/2.8 AIS is a floating element design. This allows it to be better corrected in its close range. This is the area where you will see the most improvement. I do not have the 28/2.8 AI or the AIS. I have a 28/2 Nikkor which also has a floating element design and is also very sharp. I have a number of 28/3.5 Nikkors including two AI examples. They are quite good. If I need to get close, I would rather use a 55/2.8 AIS or a 60/2.8 AF. These are much sharper in the close range than any 28.