Actors: Professional vs Amateur

I am sure most new filmmakers have had the struggles of whether to use professional actors or not. I have worked with both actors who have received fomal acting training and ones who are inexperienced, I think to answer this question, it depends heavily on the nature of your project most. But then, I guess a very general opinions about the two types are as below:

The good things about trained actors are that they know what they are doing on the set. They know how to develop their characters, they know filmmaking is all about waiting and so they wouldnt complain for long hours of wait. They sure know most of the common filmmaking terms and so you don't have to spend your valuable time on the set explaining what is a long shot or what a wide angle is..

However, trained actor, especially those who are not very experienced, could give you a lot of troubles too,..like, they always try to "act" instead of be the character, their facial expression and gesture are often too precise and too well calculated, the way they speak their lines are all too fluent. In short, they are not usually good at delivering surprise, especially when you are a new director and you are also learning at the same time, it is not easy to fine tune them to release their potentials..

As for amateur or non-professional, the bad things about them are basically the opposite of the good things the trained actors could offer. The lack of patience, the inability to build up the character, the monotone delivery of dialogues, mostly the obvious problems you can tell.

Yet what is nice about them is that you never know how far they can go. If you cast the right person, or if the actor and the character have very similar experiences, you'd be surprised by what they can do.. If you are those very dictorial type of director, working with non-professionals also gives you more power to freely manipulate them, as these actors don't have any constraint about what they can do or cannot do on the screen (as compared to those who have received training and realize what is not approrpiate to do), they tend to totally commmit themselves to and trust whatever direction the director gives (certainly you first have to build up the trust with them...) So if the director is  imaginative, the outcome can be rewarding!

All in all, it is fun working with both professionals and non-professionals, every opportunity is a new learning experience after all...