How much does the complexity or ambition of a lens design influence performance characteristics and image quality e.g. what does one give for an f/1.2 100-400mm aside from huge size and cost... To take a practical example from the extensive line of Nikkor lenses: How well does the 80-200mm f/4 AI-S lens compare to the modern 70-200mm VR AF-S et al. f/2.8 Nikkor? If one is concerned about basic performance and discounts issues around differing size, vibration reduction technology, and auto-focus etc? Secondly, to what extent are any potential differences in the performance of the two lenses mentioned likely to be related to the individual models, and to what extent are the differences inherent; e.g. how would a Leica R system or Contax SLR 80-200mm f/4 fit into the discussion (aside from the question of whether the Leica or Contax lenses are better than the Nikkor 80-200mm f/4 AI-S)?