Visual Interst: IRIS PULL

A close friend of mine inspired me to study anime, and I came across a concept that I saw used a lot. But I was surprised that it was actually rooted in the real-world camera: iris pull. An iris pull is opening or closing the iris/apeture to let more or less light into the camera. When the iris is closing, the frame gets darker and less light gets in, allowing for only lit areas or bright light effects to be seen:

Use of iris pull in Star Wars:

The two ways I found the iris pull can be used for visual interest are anticipation and divided camera space.

ANTICIPATION

One use of an iris pull as visual interest is to use it as anticipation. Anticipation is an animation principle that involves showing the audience what is about to happen. The following two examples use quick iris pulls to anticipate fully powered engines:

DIVIDED CAMERA SPACE

Lastly, one thing that animation allows is a break from rules of camera exposure to show selective iris pulls on subjects in frame for visual interest. Notice how only the car is affected by an iris pull: