The cameraman's job is to capture the image according to the director's requirements. This involves placing the camera in the right position, making sure the action is correctly in focus and in the right place in the frame. The cameraman works closely with the lighting person to make sure the image looks as best it can.
The lighting person's job is to make the scene look as natural as possible. Cameras need a lot of light to make a good sharp image.
Sometimes the lights have to be coloured to mimic certain light conditions like blue daylight or orange street lights. The lighting person may also use a reflector to bounce light around rather than using a harsh light or where there is no other light than the sun.
The sound person is responsible for the recording of the sound and dialogue. To get the best sound possible he tries to get the microphone as close as possible to the sound source. This often requires use of a boom pole which allows the microphone to be placed close to the action just out of shot. You definitely need strong arms for this as it can get quite heavy! The sound person also listens for unwanted noise and has to be careful where he places the microphone as it can cast shadows or dip into the shot.
The continuity person watches for mistakes, such as props not put back in the right place, costume problems, actors not saying the right lines, actors using the wrong hand for something, basically anything that was different from last time.
This is one of the hardest on set as they need to be really observant and have a good memory.
The clapper loader's job is to hold the numbers up in the right place, so the cameraman doesn't have to move his shot. He also records how the shot went.
The Director is responsible for making sure the actors give the best performance they possibly can. He is in charge on set and has ultimate responsibility for everyone.
Filming can be really fun, but there is a lot of waiting about whilst the crew get things ready. Sometime things just take a long time to set up! Also there are lots of takes; going over and over the scene from different angles. It can get quite boring if things aren't going well and usually takes about 4 hours do about 1 minute of on screen time.