Sometimes it can be hard to tell which lenses are the 6-element and which are the 4-element (or other) designs. For Schneider and Rodenstock, the suffixes on the model names are a clue: "-on" (Componon, Rodagon) are the 6-element designs and "-ar" (Componar, Rogonar) are the 4-element designs. I don't know how many other manufacturers use this same convention -- or at least as important, how many violate it, giving "-on" suffixes to 4-element lenses, for instance. For Fuji lenses, the EP and EX models are the 6-element designs, with EX having better coatings; Fuji's ES lenses are 4-element designs. The trickiest of the big players is Nikon, since AFAIK there are no clues in the model names; you've just got to know that (for instance) the 50mm f/4 is a 4-element design and the 50mm f/2.8 is a 6-element design.