What I meant was that although we used more expensive equipment, what has been recorded has already been recorded. But keeping it short is far easier for students, because longer videos are even more difficult. It can get boring for the audience if done poorly.
So reading up at the national libraries about film editing techniques would help. The storyline is really important, and the transitions between them are too. Alternatively, reading the cinematography books (on documentary production) at PageOne at Vivocity would be good too.
Aiming at a 1/2 hour video wouldn't be advisable, even for most poly students.