After years of attending plays, I still don't know if it is okay to applaud after a scene! I thought the whole idea was to applaud an exceptional performance and that the audience at a play was allowed to be more responsive than a concert audience.
Also, I noticed at one etiquette site that it is bad form to applaud a stage setting. I feel sorry that some very special sets didn't get applause.
Advice on applause
Dear Advice on applause,
Spontaneous applause is always appropriate if a scene, performer, or stage setting is exceptional. Below are moments when applause is appreciated for musical, opera, play, or symphony.
10 Moments Where Applause is Appreciated:
1. Concertmaster: as she/he walks in for a symphony or opera.
2. Conductor: as the conductor walks onto the podium for a symphony or opera.
3. Overture: at the end of the instrumental composition before the musical, opera or symphony begins.
4. Soloist: as the soloist enters the stage in a symphony.
5. Set Designs: beautiful, magnificent, and creative set designs when the curtain first opens for a musical, opera, or play.
6. Celebrities when they make their first appearance onto the stage.
7. After the final movement of a work in a symphony.
8. After a song or dance in a musical.
9. After each scene or act.
10. Curtain call: at the end of the musical, opera, play, or symphony. A standing ovation can be given for an outstanding performance by particular actors or the entire cast.