Working with actors
In the low budget Indie realm of filmmaking, we're generally working with theater actors or moderately experienced film actors. Sometimes we try and make do with novice actors. Sometimes we believe that our dentist would be great at playing a dentist or our mechanic would be great at playing a mechanic.
And sometimes, we put non-actors in front of the camera.
I've seen non-actors work out exceptionally well with rehearsal time, some coaching, and good direction and I've seen experienced actors struggle with weak material and lack of direction, depicting characters that an audience did not like and did not care about.
I've also see the "sure thing" non-actor who was cast in a role identical to what they really are in real life, fail.
No matter what you end up doing in regard to casting, make sure your cast has a thorough understanding of the character they are playing, the scene they're in, and if needed, the story itself. Also, be hyper-aware that when asking for additional takes of a scene, you indicate to the cast that you want them to repeat what they just did, or that you want something different. Actors really need to know if they are on the right track with regard to HOW they are portraying a character in a scene.
If a director just keeps saying "OK, lets go again," with no indication to the cast that he either A) Loves what they are doing, or, B) Wants something different, then the actors can become apathetic and/or unsure that they are doing the right things in a scene.
Non-Actors
One big thing I've noticed is that non-actors tend to be very unaware (go figure) of blocking. When a non-actor is struggling to just act (saying their lines believably) they seem to lose site of blocking and of course tend to already not have an understanding of how to "play to the camera." This can be very frustrating to a DP who may compensate by repeatedly moving camera rather than to heap more things (to remember) upon the poor non-actor.
Using non-actors limits not only believability of their character but it can also severely limit what you can do with respect to blocking and shot choices. Frustration can ensue when asking even an experienced actor to do too much in a scene but of course with enough time on set for rehearsal, these things can be worked out.
Make sure your non-actors have their lines memorized. I've seen (many times) actors show up on shoot days without having memorized their lines. Have your AD monitor non-actors and verify that they are in fact going to be prepared.
If you have access to suitable cast who may be inexperienced, it may be worthwhile to hire an acting coach to get them up to speed with regard to technique. Unless someone completely lacks any aptitude for acting at all, I've found that a few hours with a good acting coach can help a cast member immensely. This is particularly true of commercial actors (who may be former models) who essentially do little more than smile, recite lines, and walk around on camera.
Experienced Actors
Working with experienced actors can be a joy as this is where the material comes to life and when the added dimension of having another head bring more to the role is realized. One thing I've seen with some directors is they lose site (if they even had it) of the option for improv when working with actors who may have this ability. Unless there are very specific reasons for having every single line in a scene said by an actor, I believe there's a lot to be gained by allowing an actor to be loose with the dialog.
Sometimes this approach works and sometimes it doesn't, but I've seen potential portrayals by actors stifled when writer/directors insisted upon strict adherence to the script when I felt it wasn't necessary. I'd rather have a more believable portrayal that still sticks to the essence of the scene than an actor who delivers at maybe 80% because the writing is awkward or the actor (for whatever reason) has a hard time remembering the lines.
Another thing to keep in mind when working with experienced actors is they are very aware of their physical image. They are used to seeing themselves on screen, so they have an acute awareness of their flaws and almost always want to look good on camera. This can be problematic when an actor is playing a role that requires them to not look particularly "good".
Women are particularly sensitive to the potential need to have them be poorly groomed or to appear with no makeup in scenes, so be aware of this. Once makeup/hair tests are complete and you arrive at the chosen treatment of an actor, make them aware that they cannot change anything. Often, they will try to "pretty themselves up" if even a little so be prepared for this.
Some very experienced actors like to suggest ideas they may have for blocking, or variations they can provide in the way lines are said. If rehearsals were carried out as table reads only, then it's good to get input regarding blocking when on set, but some actors get a little too "involved" in the process and this can eat up time. A good director will already know what they need their cast to do but will be open to suggestions, taking advantage of good ideas when they are recognized.
©2009 Chris Santucci