When it comes to opera, it is difficult to determine the degree to which a successful production is owed to the conductor, the chief musician or the interpreters. In the case of Luigi Dallapiccola’s «The Prisoner» and Manuel de Falla’s «The Short Life,» both productions of the National Opera which are currently being performed at the Olympia Theater, the contribution of William Lacey has been acknowledged by all. Critics remarked on the change in the orchestra’s quality and ascribed it to the direction of the 30-year-old conductor from London. Christopher Alden, director in both productions, asked Lacey to participate; Olden and Lacey had collaborated before in Opera North. Despite his young age, Lacey, who has studied in Cambridge, Salzburg and Venice, has made a promising beginning that earned him the position of staff conductor at the San Francisco Opera (1998-2001). Talking about his «Athens experience,» Lacey remarked on the orchestra’s talent but also referred to some bizarre instances, such as when a musician quit in one of the final rehearsals. Lacey was brought up in the 1980s when the British National Opera was undergoing many changes. «Back then is when I saw the first truly modern productions in London,» he said. The Greek National Opera is now going through an analogous change. But Lacey sounds optimistic. «When walking in Athens I feel that I am in a cosmopolitan metropolis. Many things are happening. But we should not rush. Opera is the last to change,» he said. At the Olympia Theater (59-61 Academias, 210.361.2461) to December 1.