In 1971, Nikon made a resign of their 105mm manual lens. That same lens formula has been used for the next few decades to create several more lenses with progressively better coating and ergonomics. I recently bought the 105mm 2.5 AIS off of Craigslist on a whim. I've always heard about how amazingly sharp this lens is along with how much historical value it holds though I've never tried one myself. Being a skeptic, I tested the lens in the studio. To my amazement, it exceeded every expectation I had.
To preface this, it's obligatory for me to bring up how important this lens is in it's historical value. Apparently back in the day, everyone photo journalist had one in their bag. Being so small, I can't see why they wouldn't. Steve McCurry used this lens to take the Afghan girl portrait that everyone can recognize.
After receiving the lens, one of my major worries was simply if the lens would out resolve my D810 which has 36 megapixels. I photographed my friend in the studio, using strobe, and the results were beyond any expectation I had for it.
This is shot full frame with no cropping on D810. I shot at 5.6 to maintain some DOF yet as you can see, the DOF does fall off rather quickly behind the face near the ears. At 100% and only f5.6, you can see how this lens with a 45 year old design resolves on the D810, it's simply amazing to be able to see all the details in the eyes of the subject.
The lens has a design with considerably less glass groups and elements comparing to modern lenses. So due to that, optical correction is not as advanced as it is today. When shooting high contrast scenes with available light, there is still visible chromatic aberration around the edge of the subject. I still prefer the lens with less glass because I feel they render better and more realistic.
To me, this is a specialty lens. I only take it out of the bag when I have at least 10ft of working distance and when I'm taking photographs of a defined subject. Being the smallest lens I have in my bag currently, it hides away nicely for those tiny times when I need a lens with these reach. I got mine off of Craigslist in mint condition for only $160. I have to say, it's legendary for a reason.