The ratio between the width and height of the frame differes depending on shooting format. The most common aspect ratios are:
2.39:1
1.85:1
1.66:1
1.78:1
1.33:1
It is important to know the aspect ration you will be shooting and the ratio at which you will be exhibiting at to ensure that the composition choices you make will be preserved.
Rule of Thirds
The rule of thirds also apllies to film and video. By dividing the frame into thirds along its width and height, sweet spots are created at the intersections, providing a guide for the placement of important compositional elements.
Hitchcock's Rule
The Hitchcock rule states that the size of an object in the frame should be directly realted to its importance in the story at that moment. This is an amzingly simple rule that makes sense.
