This is excellent commentary here. I have used both the 105/2.5 and 135/3.5 extensively. "Stellar" is the prefect way to describe them. I was shocked when I noted excellent wide open performance in the 135/3.5. The 105/2.5 is nice wide open, too, but the 135/3.5 seems a "hair" better. Indeed, the modest maximum aperture in these lenses, as in others, really helps. These lens designs just have very few compromises, and the proof is in the performance.
I have a 105/2.5 AI on the way (to use on my F4s, as the AI will offer matrix metering). It will be interesting to see if there is a difference in performance when comparing the non-AI to the AI version.
I am thinking of adding the 135/3.5 AI version (again, for the matrix capability). Any views on the performance here?
Huh, my Q has seven blades (s/n 934xxx). My God it is sharp. I first realized its greatness when I shot some zebras at the zoo with b&w film.
I dropped this lens on an asphalt road one time, right on the nose (my dog pulled at his leash when I was changing lenses). The lens cap shattered, but the lens wasn't phased--save for a dent in the filter ring.