Do the clothes really help find the character? Is it a good idea to watch your own acting? And are movies sacrificing entertainment to be morally correct?

The performers participating in The Envelope's Actors Round Table wrestled with those and other questions — when they were not laughing about less serious subjects — during a wide-ranging conversation that ultimately focused on their memorable performances.

The panel was as varied in experience as the films were different. In addition to "42's" Harrison Ford, our ensemble included Lupita Nyong'o ("12 Years a Slave"), Emma Thompson ("Saving Mr. Banks"), Oscar Isaac ("Inside Llewyn Davis"), Forest Whitaker ("Lee Daniels' The Butler") and Chiwetel Ejiofor ("12 Years a Slave").

VIDEO: Watch the actors discuss their craft

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Here are edited and condensed excerpts from the conversation about how actors choose roles, what they need from a director and how clothes really can make the man (or woman):

When you are making a movie, do you actually have a sense that it's going to turn out well?

Forest Whitaker: I think there's a time, sometimes, when you're working that you can feel a transcendence and you know that something special is going on.

Oscar Isaac: I usually can tell when it's going to be bad, but I can't really tell when it's going to be good.

Chiwetel Ejiofor: You're hopeful in the moment but then you kind of have to forget about that in a way. You're just working and you're in the moment with the other actors.

Harrison Ford: I think that's important, that most of the time you don't think about the movie at all. You just think about the little meal you have in front of you and how to manage that part.

If you're lucky enough to get a great script, do you see yourself as that character?

Isaac: Choosing something is about, will it maintain my interest for the amount of time it takes to shoot it?

Ejiofor: It's always a question of sort of seeing yourself inside it, for me. Do I recognize myself somehow in this story? Because you're playing somebody else but you're also playing a reflection of yourself.

Lupita, it's a little bit different with you as this is your first film.

Lupita Nyong'o: I've done a lot of theater and one of the games I like to play when I receive a script is to, first of all, not know which character I'm going in for, just read it to get a sense of the whole story. And then, ask myself who would I play in this movie, this play, and then go and find out who I'm going in for. Because I think it gives you an objective view of the whole thing and you avoid talking yourself out of being able to play a certain character.

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When you make a decision about a movie you're going to make, how important is it that it have something to say beyond the story?

Ejiofor: Some films I think are good because, in a way, they aren't a judgment on anything. They're just telling a story and putting people through circumstances. And then there are other films that have really strong moral arcs and those are interesting as long as they don't lean too heavily on them.

Emma Thompson: Sometimes it's nice to make something that's — well, "merely" is the wrong word — entertaining. We don't make very many films anymore that are designed to make people happy from the moment they sit down and watch it to the end. We used to make entertainments that were designed to lift your spirits. We're very keen now on the moral journey and the arc and what journey are we going on with the character? And sometimes, one might be fatigued by that and wish simply to watch something like "Singin' in the Rain."

Who do you look for as a sounding board as you're considering doing something?