Actually if you're looking for a lens to use indoor for copy work where flair isn't much of an issue and also a lens which has a relatively flat field....all combined with spectacular high resolution across it's entire image field, it would be the very original and 1st generation Vivitar series 1 90mm f2.5 macro. This lens is very different than succeeding generations of that lens labeled 90mm f2.5 and f2.8, so don't confuse the two. The original 90mm f2.5 (which came in Nikon Ai or Ais versions I believe), consistantly tested at approx 105-109 line pairs/mm by f11 (on axis) and into the corners. It's sharpness is pretty astonishing.
Unfortunately I've run across a few copies that were less than desirable. At more open apertures such as f5.6 and f8, it still run rings around most current lenses. To get to 1:1, there was an matched optical adapter/tube. I haven't tested one out on recent generations of DSLR's, but suppose under proper lighting, it still will give most currently made lenses a run for their money, including the most recent Nikkor Micro's. There was an early Tamrom 90mm f2.5 macro and a early Tokina 90mm macro, but as good a performer these lenses were, the Vivitar was in a class of its own and even today that class is small if a really good copy is found.
Dave (D&A)