Some strong writing about film critics’ failure to really examine the craft of acting (right here, guilty as charged), and how cinematography has changed how actors work:
Film criticism infrequently considers whether real life is a valid criterion for judgment. It almost never reflects on the possibility that what makes a performance memorable can be precisely what makes it not believable: i.e., the larger-than-life mannerisms and bits of business with which an actor will embellish a role. Critics praised Sean Penn for the realism of his “prison yard hunch” in his Oscar-winning performance of Jimmy Markum, the ex-con in Mystic River. But why are hunched shoulders the sign of having been in prison? How many reviewers are familiar with ex-cons? Penn’s prison yard hunch is as much a fabrication as Marlon Brando’s Godfather mumble, and probably just as far from reality. It represents our idea of something, not necessarily the thing itself.
He hits the nail on the head when he says “to the extent that acting does seem more real today, it’s because the camera moves so fast off the face that it shaves off any sliver of inauthenticity.” When actors only have to be ‘in the moment’ for a second at a time, acting is more about mugging. Check out British cinema–particularly the work of Mike Leigh–for superior performances with long, long takes.
DarrenBarefoot.com 
Totally disagree. Acting for camera consists of sitting around for hours at a time trying to maintain character and realism, THEN being told to hit your mark, tear your heart out and present it to the world, all the while a camera is a two of inches away from your face, and you can feel the lights burning your skin.
And, by the by, most filmmakers shoot long takes (masters or coverage) but then cut it up in the editing room. On my set actors have to be prepared to run the entire scene (sometimes 5-6 pages of dialogue and action) over and over again – masters and then coverage, hitting their marks, mimicking their own performances for continuity, and still make me believe them.
You’re going to say theatre is harder – well, I think theatre is freeing. You do it once, and if you screw-up you cover. There is no covering on film.
Reasons is more artistically and intellectually challenging:
* The actor bears a much greater responsibility for the work of art. A good film can endure mediocre performances–good theatre cannot.
* In the same vein, theatre performers must take responsibility for the arc of their character, and demonstrate that on-stage. A film actor may consider their character’s arc, but it’s frequently rendered moot by the director and editor’s decisions.
* A two-hour play is way, way longer than the longest film scene. Theatre actors do two hours of acting without a break. Film actors do, what, 30 minutes of acting in a twelve hour day.
* There is covering on film: it’s called “another take”. In fact, if you weigh the social cost of an actor’s screw-up in the theatre compared to on film, the cost in the theatre (a distracted audience, interupted verisimilitude) is far greater than that of film. The exception being when the film actor flubs his line when a boat is exploding behind him. But then they can just correct that in post-production.
* In terms of tools, the theatre actor only has his skill or experience (along with some basic lighting, I suppose). The film actor gets cinematography, editing (a profound advantage, obviously), cinematic lighting, atmospheric music, sound design and special effects to buoy up his performance.
* Practically speaking, theatre actors have to memorize two hours worth of performance. The film actor has to memorize, at most, five minutes.
I am a stage actor, so that comes easier to me.
With theater… I have my set… that I get to know very well. My cast mates– I also get to know them very well. And you have eternity to rehearse the character!
Film- The set sucks– you don’t get time to ‘know it.’ And you have to ‘hit’ your character instantly when the director says go. So Jamie Foxx in Ray, had to go from 0 to 60 on cue… over and over and over again.
I would be interested in hearing a film actors take on performing on stage.
ive done theater and it is great im good and i know, it when i go in front of the camera i can only do one type of character me the grouch. on the stage i can be the funniest character and make people cry with laughter, on camera it does not translate at all. i think it is harder to pull a dramatic scene on film than on stage.
Over my 12 years of acting ihave come to realize that unltill you are comfortanble with who you are to be acting with and your surrounding, you will not be able to act, tro your full potentail.