For me, there are two key factors: believability and emotion.
For example, Denzel Washington often deliberately stutters when he plays a guy under pressure, and does it so well it seems natural. It's a simple technique, but it really helps portray a man who is under pressure and anxious.
Emotion...Christian Bale pours his soul int his work. Watch "The Machinist", "The Fighter", "The Prestige" and "American Psycho" for a few examples - the way he uses his voice, tone and gestures to me convey the emotion required.
Another part is timing, whether it is dramatic or comedic. Sir Anthony Hopkins played the most menacing villain in history in Dr. Hannibal Lecter simply by saying his lines in certain ways.
Anyway, back on topic - I find Ryan Reynolds over-rated. He's funny, but he's not really a great actor tbh...
And I agree - Gary Oldman and Daniel Day-Lewis are brilliant.
I agree with you but I still think that believability and emotion are two things that all film actors must have and that the vast majority do. With film especially, it is important to remember that there are many takes on one scene, with actors delivering the lines several different ways during the takes and often stuffing up. Hopkins said his lines in certain ways and did a really good job, but he would have also said those lines in different ways, with himself and the crew deciding what worked and what didn't.
And the emotion, I would call Bale pouring his soul into his work more 'commitment'. Daniel Day-Lewis would be the master at that in my opinion. However, Brando is often said to be the greatest of all and his emotion and commitment were questionable at best.
Its a combination of both.
Actors can bring a lot to a character. Take the TV show Game of Thrones for example which is based upon an actual series of books which I had read previously quite a few times. Now whenever I read parts with Jaime Lannister in it Nikolaj Coster-Waldau is what I picture in my mind because he captures what Jaime Lannister is about so well.
Watch a few B Grade movies and see what poor acting is and compare it to a strong actor. Its not just about delivering the lines well. Its about forming a connection with the audience as that character. I could read Jack Sparrows funny lines back to you in a robotic voice and you would not connect to the character. Why even have actors. Just download scripts and put them through a text to voice programme.
I also think a rubbish script rubbishness can be mitigated by good acting. Take Body of Lies which I mentioned earlier. I found it at least half decent because of Crowe and DiCaprio but the script was a load of shit. Just think of any iconic acting performance. Say Di Niro in Taxi Driver. Would that really be the same film if it starred I don't know... Kevin James.
A flat performance will sink a film just as fast as poor writing or poor direction. Film is dependent on these interlocking pieces of artistic ability from different sources. Which makes it quite interesting.
And yet actors get the overwhelming amount of praise and credit while the writers do not.
What many consider a 'flat' performance was considered good enough by the makers of that movie. A director will not tolerate a performance that he doesn't deem worthy of the script. Actors are directed in the scenes, told what to do.
B Grade films have awful scripts as well remember. Michael Caine was in quite a few yet I love watching him. Look up all the brilliant films and try and find one that has a bad script. It's no coincidence all the best performances come from the best scripts.
De Niro when he was with Scorcese was almost a co-director. It was he and Scorcese that were the driving forces behind their films, De Niro was not just an actor. They were a team and had more than a normal acting-directing relationship. You can't compare 'Kevin James' to a role. Actors are always cast first on whether or not they suit a role. It's like saying 'would Shawshank be as good if Red was played by Angelina Jolie?' The script is the basis for a good film. Scorcese had his vision of the film. He had his vision of Travis. De Niro just brought it to life, many others could have as well but since it was De Niro that's how we remember it and now we think no one else could do it as well.
I mentioned Band of Brothers earlier. Nearly all the actors were cast due to their physical resemblance to their historical counterpart, not on 'ability'. Cast by Tom Hanks interestingly. The mini series turned out to be just about the best thing ever put to film.
I can tell you the major reason why great films become great is because of the source material (script or book or true story etc) and the filmmaker's vision. Actors just add a certain spice, like icing on a cake, yet the film makers cast them and the film makers tell them what they need to do. A good actor is one that does what is best for the role and for the film, and nearly all do that. They listen to the director.
Remember, if an actor's performance is called 'flat' the director was still happy with it. That actor could have said the lines a thousand different ways yet the director was happy with the finished product.
But I do agree in some ways. In A Song of Ice and Fire I always hear the actor's voices. Although a lot of these actors were relatively unknown and not considered among the 'greats' which lends credence to my opinion that nearly all actors can bring believability and emotion to their roles. Sophie Turner never acted before but with doubtless help and direction from the crew her performance is fine.
I agree that all the parts of a film must come together to make it great, which is why it annoys me so much that actors get so much of the credit and the rest of the crew get barely any. If the acting is great, it will be 'an outstanding performance from Depp or Penn or De Niro' yet if the script is great it will be 'a good script' (unless it's by Tarantino of course).
Patrick Dempsey
Kristen Stewart
Ben Stiller
Christian Slater
Christina Ricci
Jessica Alba
Kristen Wiig
Chris Rock
Colin Farrell
What's wrong with any of these? Kristen Stewart is one I see hated on all the time, yet it's because she is involved with Twilight, a series hated by millions of people. I saw Stewart in Into the Wild, didn't know who she was, and didn't think twice. She didn't distract me from the film. Yet Twilight-haters would see her and complain about her 'poor acting', despite not even really knowing what makes a good actor, they just hate her from personal taste. It has nothing to do with 'ability', pretty much all people like certain actors because of personal taste.