An image of a December concert by the Choral Arts Society conveys some of the opu­lence they brought to the NSO’s ”Fidelio” on Thursday night. (Photo by Rebecca D'Angelo/For the Washington Post) (Rebecca D'Angelo/FTWP)

Because the opera lasted longer than your average NSO concert, I had to write my review even faster than usual, and there were a few omissions as a result. Poor Paul Appleby ended up on the cutting-room floor, which may be the fate of whoever sings the negligible role of Jaquino, but one he didn’t deserve; he sang it very honorably.

I had intended to indicate something about the semi-staging; there was a lot more onstage activity than I had expected from a concert opera, and the women both eschewed gowns in favor of character-appropriate dress (Marzelline in a black cocktail frock; Leonore in a pantsuit, hair slicked back).

Inevitably, trying to pantomime the action leads to some awkwardness when the characters are, for instance, trying to dig a grave in the basement floor. Eric Halfvarson and Melanie Diener made some appropriate straining motions, but it didn’t really add to the action, and the illusion was further hindered when Halfvarson subsequently started walking through where the grave was supposed to be. Don’t fall in, Rocco.

Another feature of the evening that I didn’t mention was the performance of the Leonore Overture No. 3 right before the finale, a tradition started by Gustav Mahler that may not work as well in a full staging as it does in a concert performance. It means a hiatus in the onstage drama, but it also gives the orchestra a chance to do some heavy lifting and really show its stuff; the orchestra played it here with verve and excitement, and it was an exhilerating lead-up to the absolutely wonderful finale. Too bad for those patrons who decided to act as if the opera was over and leave as soon as the orchestra was done; by skipping the finale, and the contribution of the Choral Arts Society, they missed one of the highlights of the NSO season.