Zoom Brush

Areas selected with this tool will pulse with selected amplitudes. It can be used for animating abstract pictures or breath. Take a look at this example:

When using the zoom brush, you can set the following parameters.

Type
Simple - changes the scale of the area linearly (motion looks sharp)
Harmonic - changes the scale of the area harmonically (motion looks smooth)

Speed - sets the effect speed

Stretch - sets the maximum zoom in

Shrink - sets the maximum zoom out

Apply animation to
background only - The effect mask covers all underlying animations.
whole scene - All underlying animations will be affected, making the effect fully transparent.

Activating the last tab allows you to change the position of the central point of the effect.