The original autofocus mechanism was complicated and hard to assemble and adjust, and its moving coil structure was hard to cool. We replaced it with a more symmetrical structure based on diaphragm flexures that were easy to fixture and assemble. We used a moving magnet and a fixed coil that was easy to cool. These changes gave us a much better performance at a fraction of the cost. Because we had allowed for this change in our modular assembly, it was easy to change from one to the other when the new one was ready. 102