I've recently been talking to Kay (the Webmaster) about getting some conversation started about Opera Stage Management and Dance Stage Management. So here's somethings that make Opera Stage Management different from musical and non musical (straight plays) Stage Management.
1. I've never seen and opera called from a booth in the back of a theater. I've always seen it called from a console backstage (stage right) with monitors to show whats happening onstage (plus a monitor to show the Maestro). True, you are not in direct contact with your light board operator or your sound board op, but I MUCH prefer this setup. I feel way to disconnected if I am calling from a booth. (Have you ever called a show from a booth, heard a crash backstage, and have been unable to get anyone on headset to tell you what happened? I just recently had a 20 gallon tank of blood burst backstage during a tech rehearsal, and I'm SO glad I was backstage so I knew what was happening and what the progress was for the cleanup.)
2. In opera, it's standard to cue entrances for the singers (and they are refered to as "singers", not "actors".) They are also given 5 minute warnings (paged over the PA system backstage) before their entrances.
3. Normally, it's not the responsibility of the SM to take blocking notes, but the responsibility of the AD. This does vary from company to company.
4. In a musical, you can give notes to your conductor/musical director concerning tempo. You cannot do that in opera. The maestro has the ultimate power over these kinds of issues, and if the singers have issues with the maestro's tempo, they should discuss it with him personally.
5. You are no longer calling from a script, but a score. The ability to read music is essential. Some stage managers I have met will argue that there are ways of calling from a score by marking timings in the score, but I don't find this to be a very precise way of keeping track.
6. Remember that in opera you are dealing with a very tempremental instrument, the human voice. I always make every effort to make sure that the singers are comfortable with their environment. The temperature should be comfortable, the air should not be too dry (to add moisture to the air, mist the stage or rehearsal space with a CLEAN Hudson Sprayer - this also settles any dust that is in the air). Since the singer's voice is their career, they do get particular about these kind of things. This should not be considered being a diva. This is the instrument essential to their career.
There are a ton of other things related specifically to opera, but these are the main differences I've noticed. Many things will, of course, vary from company to company.
